Nutrition and General Health

Answers by Leesa Klich, MSc. in Biomedical Toxicology and Nutritional Science, Registered Holistic Nutritionist, and Margarida Martins Oliveira, Ph.D., Registered Dietitian and member of the Portuguese Council of Nutritionists.

By eating more fruits and vegetables you will get more essential nutrients into your diet. These nutrients include vitamins, minerals and other beneficial plant compounds such as phytochemicals that are found in fruits and vegetables.

Fruits and vegetables are also rich in fiber. Fiber helps you feel full, lowers your cholesterol, can reduce your risk of type 2 diabetes and is great for your gut (fiber feeds your “good” gut microbes). When you feel full you are less inclined to continue eating, so eating more fiber can help you reduce the amount of food you eat without leaving you feeling hungry. It can also help you reduce your intake of unhealthy or less than nutritious foods such as heavily processed foods that tend to be high in sodium, sugars and saturated fat (and low in fiber).

Finally, eating more healthy plants can reduce your risk of cardiovascular disease, cancer and type II diabetes.

Eating a healthy plant-rich diet helps to prevent chronic diseases in several ways.

First of all, a high-fiber diet, like what you get from eating a lot of fruits and vegetables, reduces your risk of cardiovascular disease, colon and other cancers, and type II diabetes. Fiber helps to naturally lower blood cholesterol levels, which is thought to be one way that it helps with cardiovascular disease. Fiber is also the preferred food source for a healthy gut microbiota, which researchers are linking to several positive health benefits.

Your risks of developing several different types of cancers are reduced by eating a diet high in fruits and vegetables. These include cancers of the mouth, esophagus, stomach and lung. These cancer risk-reduction effects are thought to happen partly because of the antioxidant properties of fruits and vegetables. Another possible mechanism by which non-digestible fiber in plant-rich foods reduces cancer risk is that it promotes beneficial gut bacteria that metabolize the fiber into beneficial short-chain fatty acids. These short-chain fatty acids have a range of health benefits, from reducing blood pressure to lowering inflammation and cellular stress in the brain. They are anti-inflammatory and they can even encourage colorectal cancer cells to self-destruct via a process known as apoptosis.

Having a plant-based Mediterranean-style diet can also help reduce the incidence of diabetes. A Mediterranean-style diet involves eating abundant fruits and vegetables along with olive oil, legumes, whole grains and nuts, and a small amount of poultry and fish. Wine, whole fat dairy and red meat can be included in small amounts. This eating style can protect healthy people from getting diabetes and also protects some people at risk of diabetes, like those with cardiovascular disease and women at risk of gestational diabetes.

A plant-based Mediterranean-style diet works by helping to manage blood sugar, insulin resistance and cardiovascular risk factors such as overweight/obesity, blood pressure, cholesterol and inflammation.

Other studies show that eating a healthy diet plus physical activity helps to reduce the onset of type II diabetes in people who are at risk.

The U.S. Department of Agriculture measures servings of fruit and vegetables by the cup. This means that one cup (8 fl. oz or 250 mL) is one serving (except for dried fruit and leafy greens).

Examples of one serving of fruit include:

  • 1 small apple
  • 1 large banana, orange, or peach
  • 1 medium pear or grapefruit
  • 1 cup of cut or pureed fruit (e.g. applesauce)
  • 1 cup of berries (frozen or fresh)
  • 1 cup of 100% pure juice*
  • ½ cup of dried fruit

Examples of one serving of vegetables include:

  • 1 large pepper, tomato, or ear of corn
  • 1 medium potato (boiled or baked)
  • 2 medium carrots
  • 2 large stalks of celeryv
  • 1 cup of cut, raw, boiled, or roasted vegetables
  • 2 cups of lettuce or raw spinach
  • 1 cup of tomato juice

* While 100% pure fruit juice can be part of your daily fruit recommendations, choosing whole fruit is preferred because it has the added health benefits of fiber.

We’ve all heard that we need to eat our fruits and vegetables. But how many servings do we need?

According to the U.S. Department of Agriculture, an average woman should eat 1.5 to 2 cups of fruit and 2 to 2.5 cups of vegetables per day. For men, that number is 2.5 to 3 cups per day.

A simple way to increase your vegetable intake is to include at least one vegetable with every meal and have them as snacks. See additional tips on adding more vegetables to your day here.

As we age our nutritional needs change slightly when it comes to fruits and vegetables.

Women aged 19-30 who get 30 minutes or less of moderate physical activity per day( should have about 2 cups of fruit and 2.5 cups of vegetables per day. After the age of 30, women need a bit less fruit (1.5 cups), but still need 2.5 cups of vegetables per day. After the age of 50, women need 1.5 cups of fruit and 2 cups of vegetables each day.

Men who get 30 minutes or less of moderate physical activity per day* should get about 2 cups of fruit each day regardless of their age. When it comes to vegetables, men need 3 cups per day until about age 50, after that 2.5 cups per day is enough.

*Women and men who are more active may need an additional half-cup of fruit or vegetables per day.

According to the U.S. Department of Agriculture, any fruit or vegetable or 100% juice counts toward your daily fruit and vegetable intake. This includes fresh fruits and vegetables that are raw, cooked, whole, cut or pureed. It also includes fruits and vegetables that are canned, frozen, mashed or dried/dehydrated.

Having said that, it’s always a better choice to eat whole, raw fruit rather than juice. Whole fruits have additional health benefits of dietary fiber.

Also, when choosing canned fruit, choose ones that add 100% fruit juice or water instead of those canned in syrup. Syrup has added sugar that we don’t want too much of. Ideally, the sugar we eat and drink should come naturally from fruits, vegetables and unsweetened dairy products, and not added sugars.

Be especially cautious when purchasing fruit yogurts and canned fruit – look at the ingredients list of these products for added sugar that you don’t need in your diet. Sugar goes by many names: rice syrup, corn syrup, dextrin, dextrose, sucrose, fructose, agave nectar, fruit juice concentrate, invert sugar, malt syrup, malodextrin, palm sugar, turbinado. Greek and unsweetened yogurts and unsweetened canned fruits are typically best, combining higher amounts of dietary fiber without added sugars. You can always add raw fruit and a bit of honey to your plain yogurt.

By Margarida Martins Oliveira, Ph.D.

The human taste sensory system includes five primary taste qualities: sweet, salty, bitter, sour and umami. From an evolutionary perspective, it is postulated that it functions as a gatekeeper of the digestive system to ensure that we consume essential nutrients for survival while rejecting potentially harmful or toxic foods. The sweet taste perception functions primarily to detect plant-based simple sugars. Our strong attraction to sugars reflects our evolutionary need for a way to identify readily available sources of metabolic fuel, such as glucose.

The sensory pleasure derived from tasting sweet substances has an innate basis. The liking for sweet taste is intensified during childhood, a period of maximal growth when there is a nutritional need for energy-producing foods that are high in sugars, minerals and vitamins (e.g., mother’s milk and fruits).

Tasting something sweet leads to the activation of pleasure-generating brain circuitry (hedonic liking). More specifically, the information generated from the oral cavity is forwarded to the brain and transmitted to the primary taste cortex, whose neurons relay information to pathways involved in the central processing of the food reward along the dopaminergic midbrain. The activation of the brain’s reward pathway consequently releases the neurotransmitter dopamine in several other brain structures such as the orbitofrontal cortex, caudate nucleus and the amygdala.

Interestingly, a clinical study has shown while both sugar and high intensity sweeteners were able to activate the primary taste pathway in the brain, only sugars were able to activate a significant response in the brain’s reward pathway. However, individuals who regularly consume diet soda (which contains artificial sweeteners) show alterations in reward processing of sweet taste. Diet soda drinkers had greater activation to sweet taste. In this case, the brain’s reward system was incapable of distinguishing between sugar and the artificial sweetener. Research into sweetness preference demonstrates that the more often an individual is exposed to sweet foods, the higher the preference for sweet taste. The more often a sweetened beverage is consumed, the higher is the liking for the sweet taste in orange juice, for example. This can lead to overconsumption of sweet foods and beverages. This could have major health implications associated with metabolic disorders such as obesity and diabetes.

Besides influencing food preferences, sweet taste perception influences the type and amount of food consumed. Curiously, a population study revealed that total energy intake and absolute intake of carbohydrate (i.e., starch, total sugar, fructose and glucose) correlated negatively with sweet taste intensity and positively with hedonic liking of suprathreshold glucose concentrations, in a dose-dependent manner. So your liking for sweet has implications for how much energy and carbohydrates you consume.

Regarding dietary guidelines, according to the Academy of Nutrition and Dietetics “consumers can safely enjoy a range of nutritive sweeteners and nonnutritive sweeteners (NNS) when consumed within a (healthy) eating plan.” In addition, lowering the intake of simple sugars in healthy adults has been shown to increase the perceived sweetness of sugar-added foods. Thus, the take home message is to try to reduce sweet-tasting products such as sweetened foods or beverages, whether sweetened with sugar, natural or artificial sweeteners. Real sugar or not, sweetness moderation is key for a healthy brain-reward response.

More references:

by Leesa Klich

Different fruits have different nutrients, so it’s a good idea to eat a variety of fruit.

For example, you can find more of the essential mineral potassium in fruits like bananas, prunes, dried peaches and apricots, and orange juice. Foods rich in potassium can help to lower blood pressure and may reduce the risk of kidney stones and help to decrease bone loss.

Vitamin C is found in many fruits like citrus (e.g. orange), kiwi and strawberries. Not only does vitamin C help to improve absorption of iron, but it also helps the body to heal wounds.

Most fruits are rich in antioxidants, but in particular berries, cherries, peaches, pears, plums, apples, etc. High levels of dietary antioxidants may be part of the reason why diets high in fruit are associated with lower risk of diabetes and cardiovascular disease.

Fruit also contains other health-promoting compounds like the flavonoids fisetin and quercetin. Fisetin is found in apples, grapes, kiwi, peaches and strawberries. When given to mice in high doses, fisetin has reduced the inflammation levels in these animals, improved tissue function and extended their lifespan.

by Leesa Klich

The U.S. Department of Agriculture categorizes vegetables into five major groups:

Red and orange vegetables (e.g. tomatoes, carrots, sweet potatoes, squash, etc.)
Starchy vegetables (e.g. potatoes, peas, corn, etc.)
Other vegetables (e.g. cauliflower, celery, peppers, mushrooms, etc.)
Dark-green vegetables (e.g. leafy greens, broccoli, etc.)
Beans and peas (e.g. black beans, kidney beans, etc.)

A healthy balanced vegetable intake includes a variety of vegetables. The order that they are laid out above shows you how much of each to get, in decreasing order. Over the course of a week, the groups of vegetables you should get the highest amounts of are red and orange vegetables and starchy vegetables. After that aim for “other” vegetables, dark green vegetables and some beans (high in fiber, protein and also carbohydrates) and peas as well. You don’t need to have all five types of vegetable every day, but mix it up so you can have all of them by the end of the week.

by Leesa Klich

Fruits and vegetables have a lot of vitamins, minerals and other health-promoting compounds. Vitamins and minerals are essential nutrients that everyone needs every day to be healthy.

Some of the vitamins found in fruits and vegetables include:
Vitamin A
Vitamin C
Folate (vitamin B9)

Vitamin A helps keep your skin healthy, keeps your bones strong and helps with night vision. It’s also important for your immune system. Some important vegetable sources of vitamin A include orange vegetables like carrots, pumpkin, squash and sweet potatoes. Vitamin A is also found in tomatoes and leafy greens like spinach, collards and kale. Fruit sources of Vitamin A include mangoes, cantaloupe and watermelon. (More info on Vitamin A here.)

Vitamin C is an essential nutrient that helps the body absorb iron as well as heal wounds. It helps cuts and wounds heal properly and helps keep your teeth and gums healthy. Some of the vegetables high in vitamin C include sweet peppers, broccoli, cauliflower, leafy greens, cabbage, snow peas and tomatoes. It is also found in fruits such as cantaloupe, kiwi, citrus, pineapples, strawberries and watermelon. (More info on Vitamin C here.)

Folate, also known as vitamin B9, is essential for proper development of the brain and spinal cord during pregnancy. It helps the body make red blood cells and is a critical nutrient during pregnancy to reduce the risk of neural tube defects. Folate is found in several vegetables but particularly in asparagus, broccoli and leafy greens like spinach and collard, as well as in beans and lentils. It is also found in fruits such as strawberries and cantaloupe. More info on folate here.)

Some of the minerals found in fruits and vegetables include:

Calcium is essential for healthy bones, teeth, muscles and nerves. It is found in leafy greens like spinach and collards as well as in soybeans.

Iron is important for healthy blood and energy needed for all cells of the body. Its role is to help the blood transport oxygen from your lungs throughout your body. It is found in spinach, beans and lentils.

Magnesium is used by over 300 enzymes in the body and is also necessary for healthy bones. It is found in leafy greens like spinach, squash, beans and lentils.

Potassium helps to maintain healthy blood pressure and reduces the risk of kidney stones and bone loss. Vegetables rich in the mineral potassium include potatoes (sweet and white), tomatoes (and tomato sauce*), beet greens, spinach, broccoli, soybeans and legumes such as white beans, lentils and kidney beans. Potassium is also found in fruits such as bananas and kiwi.

*Watch out for high sodium content and even added sugars in some canned vegetables. Opt for fresh or frozen vegetables if possible.

Fruits and vegetables also contain a group of micronutrients called polyphenols. These are found in apples, berries, citrus, plums, broccoli, broad beans, onions and other fruits and vegetables. Many studies show that a diet high in polyphenol-rich foods and drinks protects against cardiovascular disease and type 2 diabetes.

Another health-promoting group of compounds found in vegetables are the organosulfur compounds like isothiocyanates (i.e. glucosinolates, sulforaphanes, etc.). These compounds have been found to help with inflammation, stress responses and detoxification. They also have antioxidant, antimicrobial and even potentially anticarcinogenic properties*. They are found in the Brassicaceae family of plants that includes broccoli, cauliflower, cabbage, Brussels sprouts and kale.

by Leesa Klich

Vitamin and mineral supplements aren’t a good substitute for a healthy diet rich in fruits and vegetables. For example, research on people taking multivitamins has shown no effect on the risks of any chronic diseases. Increasing your fruit and vegetable intake has health benefits beyond that of just their vitamins and minerals.

Plus, dietary supplements are not recommended for the prevention or treatment of diseases and may have unwanted side effects*.

There are some circumstances where your health care professional may recommend specific supplements for you, for example if you are pregnant, if you are on a restricted diet, and once you reach the age of 50.

*It’s probably best to get strong antioxidants and compounds such as isothiocyanates through the foods that you eat as opposed to supplements. Isolated chemicals can potentially target a single cellular response response or metabolic pathway that could possibly be detrimental if you are already battling a cancer that has co-opted this response or pathway for its own growth, for example. Particularly if you are being treated for cancer, ask your physician before taking any given supplement.

by Leesa Klich

Iron is an essential mineral that is important to help your red blood cells carry oxygen throughout the body.

How much iron do you need? Men and post-menopausal women need about 8 mg/day. If you’re a menstruating woman you need about 18 mg/day.

How do you get enough iron? While meat, poultry, seafood and eggs are known to contain higher amounts of iron, many fruits and vegetables contain it too. While the iron in animal foods is easier to absorb, there is a strategy to help the plant-based iron become more absorbable.

Some fruits and vegetables that are higher in iron include:

  • Asparagus
  • Spinach
  • Dried fruit (e.g. apricots, prunes, and raisins)

To help your body absorb more of the plant-based iron from these fruits and vegetables, eat them with other foods that are higher in vitamin C.

Food higher in vitamin C include:

  • Citrus fruits (e.g. oranges, tangerines),
  • Strawberries
  • Kiwi
  • Sweet peppers
  • Broccoli

You can combine iron-rich and vitamin C-rich fruits and vegetables by having different side dishes of iron-rich and vitamin-C rich foods at the same meal, having fruit for dessert after your iron-rich vegetable meal, or even making a salad combining them, for example spinach with orange segments and/or strawberries.

by Leesa Klich

Some of the freshest fruits and vegetables would come from your own or a neighbor’s garden. Local farmers often sell very fresh fruits and vegetables at farmers’ markets.

You can find local farmers markets in the USA and Canada.

You next best option is your grocery store. There may be a certain one that consistently has the freshest fruits and vegetables. You can also ask the people working there when they usually get fresh produce delivered to them.

by Leesa Klich

Some raw fruits and vegetables are expensive, especially ones that are already peeled, chopped and prepared for you. Look for fruits and vegetables that are in season and on sale. Another strategy is to only buy what you need and eat them all while they’re still fresh.

But you don’t have to have only fresh raw fruits and vegetables. Try them canned or frozen – remember to look for fruits that are canned in 100% juice without added syrup or sugars, and vegetables that are low in sodium with minimal added salt (“low sodium” cans and raw frozen vegetables). You can stock up on these when they’re on sale too.

Another strategy is to freeze leftovers so that you can eat them later.

by Leesa Klich

Fruits that have the highest amounts of natural sugars by weight are dried fruits – apples, berries, dates, raisins, etc.

When it comes to raw fruit, ones that are higher in sugar include:

  • Grapes
  • Pomegranates
  • Mangoes
  • Cherries
  • Bananas

Fruits that are lowest in natural sugars are:

  • Avocadoes
  • Rhubarb
  • Lemons and limes
  • Cranberries
  • Raspberries

Even though fruit contains sugar and overconsumption of sugar promotes obesity, fruit tends to have an anti-obesity effect. Fruit consumption also reduces obesity-related diseases like diabetes and cardiovascular disease. In fact, the CDC recommends a diet rich in fruits and vegetables for healthy weight management.

by Leesa Klich

The ketogenic diet is very low in carbohydrates and high in fat. The premise behind it is to restrict consumption of carbohydrates (our body’s main fuel source) and after several days we adapt to using fat for fuel. When fat is broken down it is turned into “ketone bodies” that can then be used as an alternate fuel source for most of our cells, including cells in our muscles and brain.

While there isn’t a widely accepted definition of how many carbohydrates is “very low,” most studies use a guideline of 20-50 grams of carbohydrates per day to classify a diet as being ketogenic.

Many fruits and vegetables have high amounts of carbohydrates. One medium banana has 27 grams, for example.

Some fruits and vegetables that are ketogenic diet friendly (i.e. lower in carbohydrates) include leafy greens, broccoli, cauliflower, Brussels sprouts, cucumbers, bell peppers, celery, asparagus, mushrooms, summer squash and avocados. Small amounts of berries may also be ketogenic diet friendly.

For more on eating fruits and vegetables while on a ketogenic diet, and why the carbohydrates they contain are much different than the carbs in unrefined grains and foods with added sugars, read here.

by Leesa Klich

Grains are their own category and do not substitute for fruits and vegetables. The grains category includes rice, oats and quinoa, as well as grain-based foods like breads, cereals, crackers and pasta.

The fruits and vegetables category includes legumes like beans and peas. Legumes are unique in that they can count as either fruits and vegetables or protein because their nutrient profile is similar to both.

Nuts and seeds are part of the protein category along with seafood, meats, poultry, eggs and legumes. They cannot substitute for fruits and vegetables.

by Leesa Klich

Some allergies are a nuisance while others can be life-threatening. Most food allergy symptoms appear within two hours of eating a food, although serious allergies can be immediate. If you are having a serious reaction you should immediately go to the nearest emergency room.

Over 160 foods can cause allergic reactions, however eight are responsible for 90 percent of fool allergic reactions and are classified as “major food allergens.” These are milk, wheat, peanuts, eggs, soybeans, fish (e.g. cod, bass), crustacean shellfish (e.g. crab, lobster, shrimp) and tree nuts (e.g. almonds, walnuts). Corn can also cause allergies.

Allergies to fruits and vegetables are not as common as the allergies above, but some people with pollen and plant allergies may suffer cross-reactions with compounds in foods that “look like” plant allergens to the body. For example, people who react to birch pollen may also react to proteins in apples, plums, kiwis, carrots, celery, potatoes, hazelnuts, almonds, sunflower seeds, and even spices such as oregano, basil and dill. These allergies, however, can come and go depending on the time of year.

If you think you have an allergy it’s best to speak with an allergist. Rather than avoid all fruits and vegetables that you suspect your body reacts to, you can get allergy tests throughout the year to determine exactly what is bothering you. Even those who are allergic to fruits and vegetables still should try to get the recommended number of servings each day, so if you must avoid certain ones, make sure to substitute for others in the category. Your allergist can test you (via a skin prick test for example) for allergies to specific fruits and vegetables, if you suspect you have a food allergy.

by Leesa Klich

It is recommended that most people avoid foods that are processed and foods that are high in saturated and trans fats, salt and sugar. It is also recommended that you limit their intake of red meat, processed meats and sugar-sweetened drinks. Following these recommendations can lower your risk of getting cancer, diabetes and cardiovascular disease. Even those with diabetes and cardiovascular disease can see improvement by avoiding these foods.

Here is a list of foods that you might want to avoid if you have GER or GERD (reflux).

Another important consideration is not just what you eat, but how much you eat and when you eat, particularly with regards to weight management and management of related diseases. Having healthy foods in adequate portion sizes, ideally consumed primarily during daylight hours, is key to optimal health.

by Leesa Klich

A balanced diet and adequate nutrient intake are important for people with cancer. Nutrition-based interventions, exercise and even mindful eating practices can be leveraged to reduce some side effects from treatment. The main things to keep in mind are to maintain a healthy body weight and strength. Malnutrition is a risk for some people with cancer because the condition and its treatment can affect a person’s taste, smell, appetite and ability to eat enough food and absorb nutrients from food. In this case, eating enough protein and maintaining an adequate calorie intake are very important to help with energy levels and the ability to fight infections and heal wounds. This may include adding extra dairy or eggs to the diet.

Depending upon side effects, there may be different nutrition recommendations. Some cancer patients, such as breast cancer patients, tend to gain weight during treatment. This weight gain has consistent negative impacts on treatment effectiveness and recurrence, such that nutrient restriction (particularly cutting out added sugars) and even time-restricted eating schedules may be beneficial.

For all three types of diabetes (type I, type II and gestational), there are guidelines to help you eat well. Recommendations include eating more fruits, vegetables, whole grains and low-fat dairy. Avoid foods that are higher in calories, saturated and trans fats, sugar and salt. Drink water instead of sweetened beverages. These recommendations can be made easier by making sure half of your plate is fruits and vegetables, one quarter is lean protein and the last quarter is whole grains.

When it comes to cardiovascular disease, the recommended diet includes fruits and vegetables, whole grains, low-fat dairy, fish, lean meats and poultry, eggs, nuts and seeds, legumes and vegetable oils (with the exception of coconut and palm oils). Avoid foods and drinks that are higher in salt, saturated and trans fats, added sugars and alcohol.

There is also a diet specifically designed for high blood pressure called DASH (Dietary Approaches to Stop Hypertension). This diet has been shown to lower blood pressure and reduce blood cholesterol. Instead of recommending specific foods, it provides daily and weekly nutrition goals to reduce intake of saturated and trans fats and sodium while increasing intake of potassium, calcium, magnesium, fiber and protein. In fact, the DASH diet can also reduce the risk of kidney stones.

To reduce the risk of kidney stones, reduce your intake of animal protein and sodium while increasing your intake of calcium from foods. Certain kidney stones created from oxalate can be reduced by reducing intake of oxalate-containing foods like nuts, peanuts, rhubarb, spinach and wheat germ.

For nonalcoholic liver diseases, risk can be reduced with a few dietary recommendations. First, replace saturated and trans fats with unsaturated fats, particularly omega-3 fats. Avoid excess alcohol and foods and drinks high in sugar.

by Leesa Klich

Vegetarian eating patterns based on whole foods can be very healthy and reduce one’s risk of cardiovascular disease, obesity, diabetes and some types of cancers. However, there are a few nutrients that may be too low in vegetarian diets; these are protein, calcium, iron and vitamin B12.

Meat is known to be a great source of protein. Plant-based sources of protein include beans and lentils, oatmeal, nuts and quinoa. Meat-free sources include eggs and dairy.

Calcium is found in the following plants: leafy greens, broccoli, almonds, sesame seeds and fortified foods like plant-based milks, orange juice and tofu. Meat-free sources of calcium include dairy products.

Iron is one key essential mineral that is more abundant in meat, poultry and fish. Additionally, the iron in meat and animal-based foods is called “heme” iron and our bodies can absorb that more easily than the “non-heme” iron found in plant-based foods. Plant-based sources of iron include soy and tofu, leafy greens, beans, nuts and seeds. Iron is also found in eggs and enriched breads and pasta. When eating plant-based sources of iron, include a good source of vitamin C to increase its absorption.

When it comes to vitamin B12 it’s important to choose fortified plant-based foods like soy milk and cereals. Vitamin B12 is also found in eggs and dairy.

by Leesa Klich

The macro ratio (the relative amounts of carbohydrates, protein and fat in your diet) that works best for you may depend on your age, gender and health conditions such as diabetes, as well as other individual factors. There are a few tests that your doctor may order if he/she suspects that you may have diabetes or prediabetes. These include the fasting plasma glucose (FPG) test, A1C test or the oral glucose tolerance test (OGTT).

There are some emerging resources for precision nutrition based on very new research. Results from these non-diagnostic tests should be discussed with your doctor. For example, InsideTracker can help create a personalized action plan to help you reach your health goals. This plan incorporates nutrition, supplement, fitness and lifestyle recommendations based on your blood, DNA and lifestyle habits. Another example of precision nutrition involves microbiome analysis (of the microbes in your gut), which may help you to better manage various gut conditions.

Nutrition and Brain Health

Answers by Margarida Martins Oliveira, Ph.D., Registered Dietitian and member of the Portuguese Council of Nutritionists).

Dietary factors can affect multiple brain processes such as cognition, emotion and behavior. They do this by regulating neurotransmitter pathways, synaptic transmission between brain cells, membrane fluidity and signal-transduction pathways. Nutrients that preserve brain health include omega-3 polyunsaturated fats (omega 3-PUFAs) and folic acid.

Omega 3-PUFAs regulate several processes within the brain, such as neurotransmission and neuroinflammation. These are key processes in cognition. Foods highest in omega 3-PUFAs include vegetable oils, walnuts and Brazil nuts, as well as poppy, flax and chia seeds. Almonds and olive oil are also relatively high in these fatty acids.

Folic acid prevents cognitive decline and dementia during aging and is found in various foods, including leafy green vegetables (e.g. spinach and kale), citrus fruits (e.g. orange juice), whole grains and beans, etc. Foods high in omega 3-PUFAs and folic acid are usually included in whole-food plant-based diets, which focus on plant foods like vegetables, fruits, whole grains, legumes, nuts and seeds. If animal products are eaten, they should be eaten in smaller quantities compared to plant foods.

Importantly, impaired glucose tolerance and insulin resistance, as observed in diabetes, are associated with cognitive impairments such as decreased performance on attention and memory tasks. Impaired blood sugar control and insulin resistance could lead to Alzheimer’s Disease. Thus, it is advised to follow a healthy diet and avoid refined sugars for healthy brain function.

More References:

Cognitive function encompasses different mental processes such as attention, working memory, language use, perception, learning, problem solving and decision-making. Cognitive decline associated with normal aging can be attenuated by a wide variety of factors, including improved nutrition through diet. Diet and even nutrient timing can affect neuronal plasticity or the ability of the brain and its cells to change and adapt their structure, function and connections.

The brain is highly susceptible to oxidative damage due to its high metabolic load and abundance of oxidizable material (e.g. membranes of neural cells). Antioxidant activity thus plays an important role in the prevention of cognitive disorders.

Nutrients with antioxidant activity include B vitamins (including B6, B12 and folate), vitamins C, A, and D, and polyphenols (e.g. resveratrol, flavonoids, etc.). These are all highly present in vegetables and fruits. In fact, a meta-analysis study revealed that increased consumption of fruit and vegetables is associated with a reduced risk of cognitive impairment and dementia in humans.

Examples of vegetables and fruits with high antioxidant content include: sweet potato, carrot, pumpkin, tomato, spinach, kale, cabbage, broccoli, watercress, pepper, cauliflower, strawberry, blueberry, grape, mango, papaya, apricot, kiwi, etc.

A great example of a healthy dietary pattern rich in vegetables, fruits and legumes is the Mediterranean diet, which is associated with higher verbal learning and memory performance.

More References:
Fruit and vegetable intake and cognitive impairment: a systematic review and meta-analysis of observational studies. Eur J Clin Nutr 2018;72(10):1336-1344.
Nutritional modulation of cognitive function and mental health. J Nutr Biochem 2013;24(5):725-743
Dietary Factors and Cognitive Decline. J Prev Alzheimers Dis 2016;3(1):53-64.
Krause’s Food & the Nutrition Care Process. St. Louis, Missouri, 2017.

The ketogenic diet mimics the physiological alterations observed in prolonged fasting, when the body is maining using body fat or dietary fat for energy. Burning fats for fuel during a ketogenic diet or fasting promotes ketone body production and utilization. The ketogenic diet comprises a high proportion of fat, adequate protein and low carbohydrates.

The ketogenic diet has been implemented as a treatment to pharmacologically resistant epilepsy. It also has some beneficial effects on neurology function, such as anti-oxidation and anti-inflammatory activity that could be neuroprotective in some brain diseases such as Alzheimer’s disease.

The putative neuroprotective effects of ketone bodies have been associated with a decrease of oxidative damage and the modulation of inflammatory status in the brain. However, the ketogenic diet has common adverse gastrointestinal side effects including vomiting, constipation, diarrhea and hyperlipidemia. Thus a ketogenic diet should only be administered within a limited period of time and under careful clinical supervision of dietitians, even if you are healthy.

More References:

The Mediterranean diet is associated with better cognitive performance in memory, language and visuospatial perception. It is also associated with lower dementia rates, as shown in a population cohort study. Mediterranean diets typically include the consumption of items such as non-refined cereals, fruits, vegetables, legumes, whole grains, nuts, potatoes, fish and olive oil. They typically involve avoidance of meat and meat products, poultry and full-fat dairy products.

Furthermore, nutritional studies show that caloric restriction or reducing food intake can significantly influence healthy aging, including brain aging. Caloric restriction is the most effective intervention known to date that has the potential to robustly increase the lifespan of several species, from yeast to mammals. Caloric restriction has been shown to improve healthy lifespan in non-human primates, which share a high degree of similarity to humans. According to Dr. David Sinclair’s theory, caloric restriction is a “moderate stress” that produces a highly conserved stress response. This response modifies multiple cell signaling pathways that regulate cell growth (think tapping the brakes on cancer cell growth), metabolism, oxidative stress response, DNA damage repair and inflammation. It causes adaptive responses in cells and organs that prevent further damage from other stresses. This response in the end increases the organism’s chance of surviving adversity.

Intermittent fasting, a variation of caloric restriction, has also more recently been shown to have beneficial health and brain health effects. These dietary regimens seem to prevent some age-related neuronal damage, preserve learning and memory and may have a significant benefit for debilitating and prevalent neurodegenerative disorders such as Alzheimer’s, Huntington’s and Parkinson’s diseases.

More References:

Nutrition intervention in Alzheimer’s disease aims to effectively enhance food intake and prevent weight loss, poor eating habits, depression, impaired memory and self-feeding difficulty. Moreover, elevated homocysteine levels are associated with higher risk of cognitive impairment and nutrients such as folic acid, vitamin B6 and vitamin B12 can act as cofactors for the methylation of homocysteine, lowering homocysteine levels.

Escott-Stump (2011) gives the following nutrition-related suggestions for patients with Alzheimer’s disease:

Meals should be taken at regular and consistent times each day. Allow sufficient time for eating and avoid distractions (for example, use calming background music).

Adequate fluid intake (water, 100% juice, milk, etc.) is essential to avoid dehydration.

Include nutrient-dense foods that are high in antioxidants and folic acid (leafy greens, orange juice, broccoli), which may lessen decline of cognitive function. Consume color-rich fruits and vegetables such as blueberries, cranberries, strawberries, spinach, kale, broccoli, oranges, and other citrus fruits.

Consume more oily fish (salmon, halibut, trout, and tuna) for omega-3 fatty acids. Cut back on saturated fats, which increase brain beta-amyloid levels, and avoid high-fat dairy products, fast food items, fried foods and processed foods.

Since vitamin B12 is not found in any plant foods, prefer vitamin B12 from low-fat red meat and low-fat dairy products.

Increase the intake of foods rich in potassium to preserve muscle mass (e.g. fruit and vegetables).

Finger foods are easier to eat and help to maintain weight (e.g. sandwiches cut into four, cheese cubes, pancakes or waffles cut in smaller pieces, hard cooked egg halves, chicken strips, julienne vegetables).

Nutrition intervention in Parkinson’s disease aims to supply dopamine to the brain, improve the ability to eat, correct alterations in gastrointestinal function (i.e., increased transit 
time, heartburn, constipation, and control body weight, which may fluctuate from either reduced mobility or the inability to ingest sufficient energy quantities.

Escott-Stump (2011) gives the following nutrition-related suggestions:

The timing of levodopa administration should be monitored to avoid conflicting responses to protein at meal times.

When sucking or swallowing reflexes are reduced, use semisolid foods rather than fluids. Adequate hydration is essential, especially when thickened liquids are needed. Drooling may be a problem: plan diet and proper consistency of foods according to results of swallowing evaluation (e.g. cut, mince, or soften foods as required).

Increase intake of fiber (e.g. add crushed bran to hot cereal or try prune juice).

Prefer foods such as vegetable oils, nuts, green tea, coffee, turmeric and antioxidant-rich fruits and vegetables.

A multivitamin–mineral supplement may be beneficial, especially for vitamins C, E, and the B-complex vitamins.

When using MAOIs anti-depressive medications, follow the tyramine-restricted diet: avoid aged and fermented meats, sausages and salamis; pickled herring; spoiled or improperly stored meat, poultry and fish with changes in coloration, odor or mold; broad bean pods; sauerkraut; aged cheeses; red wines and all varieties of tap beer and beers that have not been pasteurized; over-the-counter supplements containing tyramine; concentrated yeast extract; soybean products such as soy sauce and tofu.

Nutrition intervention in brain cancer aims to counteract side effects of therapy (e.g., radiation, surgery, chemotherapy), avoid constipation and monitor carefully for elevated blood glucose levels that 
may occur with corticosteroids that are used to control brain edema.

Escott-Stump (2011) gives the following nutrition-related suggestions:

Regular and attractive meals are important to help poor appetite. Keep in mind that sense of smell may have declined recently. Alter texture and liquids when feeling difficulty or discomfort in swallowing.

If oral diet is possible, include fish, fruits, vegetables and adequate fiber. Include green tea, food sources of beta-carotene and fish oil to enhance neuroprotection.

Limit salt intake (maximum 4–6 g/day) to correct cerebral edema.

Ketogenic diets may represent potentially viable treatments to limit oncogenesis because cancer cells preferentially use glucose for energy, and the ketogenic diet provides ketone bodies for energy to the brain. Nevertheless, ketogenic diets should be administered under careful clinical supervision of dietitians.

More References:

To date, there is no strong scientific evidence to support any particular migraine diet. Some lifestyle triggers appear to be common across migraine patients (caffeine, alcohol, skipping meals), whereas some foods or food components are reported to increase the likelihood of a migraine attack in susceptible individuals. However, these food triggers appear to be highly individualized. Thus, priority should be given to monitor the most common triggers observed before your migraine attacks.

Evidence does not support elimination diets to identify triggers for migraine prevention. Moreover, migraine sufferers often note that missing meals can trigger headache, so is important to make time for small frequent meals. Migraine attacks are often due to multiple factors and there are many non-dietary trigger factors. For example, when you’re already not sleeping well, not exercising or going through the ”let-down” effect of a stressful period, skipping a meal may make it more likely to have a migraine attack. Therefore, it is the combination of all of these different things that contribute to the migraine, and not just one factor. Try to engage in a healthy lifestyle with regular daily meal times, in addition to maintaining a regular sleep schedule.


Some foods or beverages can interact with certain drug medications. For example, some foods/drinks can lower the levels of enzymes in your liver responsible for breaking down medications, causing blood levels of an interacting drug to rise, potentially leading to toxicity. On the other hand, alcohol should be avoided because it can add to the side effects of various medications.

Moreover, there is meal-drug interaction as drug absorption will depend on meal timing: some medications should not be taken on an empty stomach due to stomach discomfort (e.g. non-steroidal anti-inflammatory drugs); whereas some medicines work better when you take them on an empty stomach (e.g. sleep medicines should not be taken with a meal or right after a meal).

Other recommendations to prevent drug-food interactions include:

Avoid grapefruit juice while using statins to lower cholesterol, like atorvastatin, lovastatin or simvastatin. The result can be muscle pain or even severe muscle injury known as rhabdomyolysis.

Avoid cranberry juice or cranberry products while using anticoagulants because they can change the effects of warfarin.

Avoid consuming dairy products (like milk and yogurt) or calcium-fortified juices alone while using ciprofloxacin antibiotics. However, you can take ciprofloxacin with a meal that has these products in it. The presence of antacids, such as calcium hydroxide and calcium carbonate, could modify antibiotic dissolution rate and reduce its absorption, leading to therapeutic failure.

Oral chemo-therapeutics used in cancer therapy might interact with high-fat meals, calcium-containing foods/supplements and with grapefruit. Oral chemotherapeutics have a fairly narrow therapeutic index and potential drug interactions can cause significant changes in total absorption of these medications.

Avoid foods and drinks that contain tyramine while using anti-depressant monoamine oxidase inhibitors (MAOIs) or oxazolidinone antibiotics. High levels of tyramine can cause a sudden, dangerous increase in your blood pressure. Tyramine is present in cheeses, especially strong, aged, or processed cheese; aged, pickled, fermented or smoked foods.


    • Food-Drug Interactions: a guide from the National Consumers League and U.S. Food and Drug Administration. U.S. Department of Health and Human Services. Food and Drug Administration.

A Review of Food-Drug Interactions on Oral Drug Absorption. Drugs 2017;77(17):1833-1855.
Oral chemotherapy food and drug interactions: a comprehensive review of the literature. J Oncol Pract 2014;10(4):e255-268.

Humans and animals start secreting metabolic hormones in anticipation of a pending meal. This response can also occur through stimuli or cues that reliably predict food availability. Stimuli such as the smell and sight of food, time of day, circadian time, time elapsed since the previous meal and specific environments where meals have occurred in the past can all trigger responses in the brain.

Based on food-related stimuli and cues, the brain sends signals to secretory organs before you even ingest your food. Several hormones are secreted in order to increase sensitivity to taste and smell and the gastrointestinal tract becomes primed to digest a meal. These hormones include glucagon-like peptide 1 (peaks around 1 hour before a meal), ghrelin (peaks around 30 minutes before) and insulin (10 to 15 minutes before). Other meal-related responses are also activated before eating actually begins, including salivation, thermogenesis, secretion of gastric acid and increased gastrointestinal motility.

Once food is in your mouth, there is contact between the food and sensory receptors that transmit information about the quantity and nutrient composition of the meal. During this phase, orosensory stimuli arising from palatable food (e.g., sweet and fat taste) provide positive feedback to the brain that increases the rate and amount of food consumption during a single meal. Interestingly, a food that is highly palatable at the beginning of a meal becomes progressively less palatable* by the end of a meal when satiation is attained.

*If you eat a large piece of cake very slowly, you might notice this happening! This attentiveness to how your food tastes as you eat is known as intuitive or mindful eating.

On the contrary, a bitterness taste suggests that a food or food component might be poisonous or toxic and our brain is primed to differentiate this in order to keep us healthy.

Information related to ingested food is transmitted from the stomach and small intestine to the brain via the vagal nerve. More specifically, the vagal nerve detects the stretch of the gut wall and signals such as cholecystokinin, glucagon-like peptide 1, peptide YY and serotonin released by gut enteroendocrine cells in response to nutrients. The vagal nerve then activates neurons in a specific brain area, the nucleus tractus solitarius, promoting satiation and meal termination. All of this happens relatively quickly during and after a meal.

In contrast, long-term feedback that suppresses hunger arises from your energy stores and is transmitted by a hormone called leptin. This hormone is produced by adipocytes, thus circulates in proportion to fat stores. Leptin primarily signals neurons in another brain structure, the hypothalamus, to indicate whether fat stores are adequate in order to decrease food intake.

More References:

The motivational “wanting” to eat, i.e., food craving, can be triggered by external cues, hunger states or simply imagining the sight, smell and taste of palatable foods. Food cues in the surrounding environment activate the brain reward system. This reward system preferentially engages our attention towards calorie dense foods. This happens especially when we are hungry, increasing our motivation to eat (i.e. food craving). More specifically, if we pay attention to food cues surrounding us in our daily life (e.g., the appetitive smell of a freshly baked chocolate cake or if we see golden crispy french fries or a delicious melted cheese pizza), the brain is triggered to search for calorie dense foods. And this triggering is augmented when we are hungry.

Therefore, on a daily basis, try to have a healthy balanced diet and avoid obesogenic environments or environments that encourage you to eat unhealthy and that have the potential to induce food cravings and overconsumption. For example, avoid strolling around pastries, supermarket shopping when you are hungry or walking by takeaway outlets in shopping areas.

Whenever you experience food cravings, “try not to immediately give in to the urge to consume the food, but rather focus on and accept the bodily sensations and thoughts that accompany this urge,” a mindfulness-based technique used by Alberts et. al (2010). By using this exercise, “the primary aim of this approach is not to limit food intake, but to increase awareness of the automatic pattern that usually emerges in case of food cravings,” Alberts et. al (2010) explains.

More References:

LIFE it. Love it. Share it.