Glen Pyle, PhD
Glen Pyle is a Professor of Biomedical Sciences at the University of Guelph and an Associate Member of the IMPART Investigator Team Canada Network at Dalhousie Medicine.

Glen Pyle, PhD
Glen Pyle is a Professor of Biomedical Sciences at the University of Guelph and an Associate Member of the IMPART Investigator Team Canada Network at Dalhousie Medicine.

They say that a fine wine improves with age. But not everything gets better as we get older. Muscles are near the top of that list.

What you’ll find in this article:

What is sarcopenia? | Causes | Prevention

What is Sarcopenia?

Sarcopenia is the loss of muscle mass and function that occurs with age. While it is normal for most people to lose about 1% of their muscle mass each year after the age of 30, people with sarcopenia have a greater decline. There is no single test for sarcopenia. Diagnosis is based on a series of tests that measure muscle size, strength, and the ability to perform activities like walking, climbing stairs, or grasping objects.

Sarcopenia in elderly. Replacement of muscle tissue with fat in aging process. Vector illustration
Sarcopenia is the loss of muscle mass and function that occurs with age. During sarcopenia muscle tissue is replaced with fat.

What causes Sarcopenia?

Muscle size and function depend on many factors and disrupting any of these could lead to sarcopenia. It is, therefore, not surprising that there is no single cause of sarcopenia. Instead, studies have reported connections with several circumstances. Insufficient dietary protein, Vitamin D deficiency, and oxidative stress are some of the more common elements associated with sarcopenia.

Low dietary protein

A key component of muscle are amino acids, which are the building blocks for muscle proteins. The source of amino acids is dietary protein. The gut takes up amino acids which acts as a strong signal to the body to initiate processes that build muscle.

The recommendation for daily protein intake is about 1 g/kg for sedentary adults, and up to 1.7 g/kg for people who exercise. There is evidence to suggest that as people age, their sensitivity to dietary protein decreases, and the amino acids that are taken in through food are less potent stimulators for muscle growth. While excessive dietary protein intake can create health problems, increasing dietary protein in older people can be done without reaching these levels, and the increased dietary protein may overcome the insensitivity to amino acids that normally comes with aging.

High protein food for body builders as meat, fish, dairy, eggs, buckwheat, oatmeal, nuts, bean, pumpkin seed and sunflower seed. Top view.
Low protein intake is one cause of sarcopenia. The recommendation for daily protein intake is about 1 g/kg for sedentary adults, and up to 1.7 g/kg for people who exercise.

Vitamin D defficiency

A loss of muscle strength is a common sign of Vitamin D deficiency. The Longitudinal Ageing Study in the Netherlands reported that older adults with low levels of Vitamin D (<25 mmol/L) were twice as likely to have sarcopenia. Systematic reviews of research studies show that Vitamin D supplementation corrects muscle dysfunction in adults with a Vitamin D deficiency.  Adults with low levels of the nutrient benefit the most. Adults with normal Vitamin D levels have no advantage after supplementation.

Oxidative Stress

Reactive oxygen species are a part of normal metabolism, but excessive production can cause damage to numerous tissues in the body, including muscle. Antioxidants coming from the diet keep oxidative stress under control. These include  selenium, flavonoids, and Vitamin E. People deficient in selenium and Vitamin E are more likely to develop sarcopenia, and Vitamin E supplements can reverse some muscle weakness. However, Vitamin E does not increase muscle size or strength in people whose Vitamin E levels are in the normal range.

Hand of a woman holding vitamin E, urban sunset background. Healthy eating, medicine, health care, food supplements and people concept
Supplementation with Vitamin E and D and slow down muscle loss in people with nutrient deficiencies.

Aging leads to reduced food intake

After the age of 40, energy intake can decrease by 25%, a process that is called the ‘anorexia of ageing’. The decline in food consumption is a result of a number of ageing-related changes, from a loss of taste to changes in hormones that control appetite. Depression and dementia; physical issues including gastrointestinal conditions and difficulties swallowing; or socioeconomic challenges like poverty can all exacerbate food intake decline. Globally the risk for malnutrition in older adults varies widely, but up to 25% of adults over 65 years of age are at risk for malnutrition. These dietary challenges can create a stress on the body that ultimately results in a loss of muscle mass and strength, leading to sarcopenia.

How can I prevent Sarcopenia through diet and exercise?

A balanced diet is best

One problem with identifying a single dietary component as a target for treatment of sarcopenia is that this fails to recognize the complexity of diets. Often a dietary deficiency in one nutrient occurs in combination with other deficits. Focusing on individual elements also does not take into consideration how nutrients can interact.

Studies find that diets rich in fruits, vegetables and oily fish help maintain muscle strength. While older individuals may require some dietary modifications like increased protein intake, overall a balanced diet is sufficient for normal muscle function and to slow the effects of ageing, unless a specific nutritional deficiency is identified.

Up your intake of Omega-3 fatty acids

Omega-3 fatty acids are essential fats for the body. They help to stabilize cells and provide energy. Since the body can’t make these fatty acids it must obtain it from the diet or from supplements. Fish and fish oils are excellent sources of omega-3 fatty acids, as are Brussels sprouts, walnuts, and flaxseed. Some foods like milk, eggs, and yogurt can be fortified with omega-3 fatty acids by adding algae oil. While there is evidence for moderate health benefits of dietary omega-3 fatty acids, the use of supplements to improve health remains unproven and taking an excessive amount can cause bleeding and interfere with the immune system.

There is some evidence suggesting that omega-3 fatty acid deficiency plays a role in sarcopenia. A meta-analysis showed that dietary omega-3 fatty acid levels were decreased in people with sarcopenia. A systematic review of 66 research studies testing the benefits of omega-3 polyunsaturated fatty acids found supplementation increased muscle mass and improved function.

Evidence for a link between omega-3 polyunsaturated fatty acids and sarcopenia is positive, but of moderate strength. Although a connection has not been firmly established, it has been suggested that these dietary fatty acids may protect muscle by stimulating muscle cells to take up amino acids and build proteins or by acting as buffers against damaging oxidative stress.

Exercise: The Miracle Cure

Resistance training – commonly referred to as ‘weight training’ – is a recommended treatment for sarcopenia. A study of 50 men and women between 50 and 79 years of age tested the ability of a 24-week resistance program of low or moderate resistance training to improve muscle in people with sarcopenia. Participants completed 3 sets of 14 repetitions each day of exercise, three times a week. Low intensity exercise benefitted muscle size, but moderate exercise had a larger impact on size and function. A review of 22 studies found resistance training 1 to 3 times a week up to 18 weeks improved muscle size and strength in people 75 years and older.

Resistance training can prevent sarcopenia.

One-Two Punch of Exercise and Protein

A combination of protein supplementation and exercise stimulates the uptake of dietary protein and the growth or maintenance of muscle. A study by Dutch researchers found that moderate intensity weight-lifting increased the uptake of dietary protein and synthesis of muscle proteins in men over 70 years of age to levels similar to men under 25 years old. A review of 22 randomized clinical trials by this same group of researchers found similar muscular benefits of combined exercise and protein supplements in people who participated in resistance training programs over several weeks. These studies show that a combination of resistance exercise and moderately increased dietary protein may limit the risk of sarcopenia.

How to strength-train to prevent sarcopenia

Exercises that target large muscle groups of the lower body are important because of their role in daily life, from rising from chairs to walking. However, you should rotate muscle groups to give a balanced approach. Initial weight training should be done using 30-60% of the maximum weight, and 6-12 repetitions. You can progressively increase the load to 70%, with the long-term goal of reaching 85% of the maximum. Similarly, as your strength improves, you can increase the number of sets for each exercise to a maximum of three. Separate sets with 1 to 2 minutes of rest, and follow each exercise with 3 to 5-minute breaks.

Starting with a single weight training session a week is a good way to start. Eventually, do resistance training sessions twice a week with several days of separation to allow for muscle recovery. Although a third session may add to your muscle strength, there is risk of injury. A better option is to do other activities that provide more balance to your exercise program.

While the core issue with sarcopenia is a decrease in muscle strength, broad exercise programs involving weight training, aerobic activities, and balance exercises helps to provide a well-rounded program to improve overall fitness and health.