Do Dietary Supplements Prevent Muscular Atrophy and Strength During Disuse?
by Benjamin Bunting BA(Hons) PGCert
Written by Ben Bunting: BA, PGCert. (Sport & Exercise Nutrition) // British Army Physical Training Instructor // S&C Coach.
Muscle atrophy can cause one arm or leg to look smaller and feel weak. Muscle atrophy from disuse can be reversed with regular exercise and a healthy diet.
Dietary supplements (also called food supplements or nutritional supplements) are products designed to give you nutrients that might be missing from your diet, typically in the form of pills, capsules, tablets, powders and liquids. They can be made from whole foods or manufactured synthetically. They are not intended to treat diseases or health conditions.
Vitamins and minerals are the most common dietary supplement ingredients. Vitamins are micronutrients that help with normal metabolism, and they come in the form of multivitamins or single-vitamins. The most common vitamins are thiamine, riboflavin, niacin, pantothenic acid, vitamin B6, biotin, folate and vitamin C. Minerals include sodium, potassium, calcium, magnesium, phosphorus, iron, zinc, copper, manganese and chromium. They are most often available in multi-mineral supplements.
Plants and herbs are also a popular class of dietary supplements. Several of these are popular among bodybuilders, including whey protein, creatine monohydrate and beta-hydroxy beta-methylbutyrate (HMB). The best way to get the nutrients your muscles need is through whole foods.
However, can supplements prevent muscular atrophy and muscle strength loss from periods of disuse?
There are many different protein supplements on the market which are used by athletes, recreationally active people and soldiers to increase muscle mass and improve exercise performance. Some are also used to protect against the loss of muscle mass strength that occurs during disuse. A protein supplement should be part of a healthy diet and used in conjunction with other dietary supplements to achieve the best results.
During disuse, your muscles lose their size and strength at an accelerated rate. This loss is due to a number of factors, including the disruption of your muscles’ ability to stimulate protein synthesis, a reduction in your body’s natural metabolites (like glucose) and an increased rate of breakdown of proteins in your muscles. The latter is driven by the increase in stress hormones and decreased insulin sensitivity that occur during disuse.
The type of protein you consume will influence the rate at which your muscle fibres can be stimulated to synthesise proteins. For example whey protein is rapidly digested and it’s a good source of an amino acid called leucine. Leucine is a key signalling nutrient that helps to turn on muscle protein synthesis and inhibits protein break down.
High quality whey protein will therefore accelerate the recovery of muscles that have been stressed by demanding training sessions. It will also help to slow down the deterioration of muscle strength during the early weeks of disuse when the rate at which your muscles lose their strength is most rapid.
In addition to increasing protein synthesis, a high quality protein supplement will also contain other important nutrients that support the immune system and promote muscle tissue health such as branched chain amino acids and glutamine. Branched chain amino acids are important to prevent inflammation, which is the main driver of protein degradation in muscles. In addition, research has shown that the dietary intake of these amino acids reduces the loss of muscle strength and power during disuse.
The best way to get these critical nutrients is by eating a diet rich in fish, chicken, turkey, eggs and dairy as well as whole grains and vegetables. However, for some people a formulated protein supplement drink or bar will be more convenient to take when on the go.
Carbohydrates provide a large portion of your body's energy. They are found in many healthy foods including whole grains, fruits, vegetables and legumes. The healthiest carbohydrate sources are unprocessed or minimally processed foods that contain a variety of nutrients and fiber. They include whole grains, milk, fruit and juices, dried beans, potatoes and popcorn. They do not contain any added sugars and should be incorporated into your diet as part of your overall daily intake.
In chemistry, the term carbohydrate refers to any substance with carbon, hydrogen and oxygen atoms and usually with a ratio of 2:1 (water is typically considered to have this ratio). This stoichiometric definition has been challenged, however, by chemicals that do not conform to it but are nevertheless classified as carbohydrates, such as formaldehyde and glycolaldehyde. The biological meaning of carbohydrate has evolved over time and now includes a broad range of molecules that are neither fats nor proteins, such as simple sugars, starches, gums and cellulose.
The simplest carbohydrates, also known as monosaccharides, are the sugars that form sucrose, fructose and lactose. They are cleaved during cellular respiration into glucose and a number of other intermediates, with the release of energy in the form of ATP. The energy obtained from the breakdown of a carbohydrate molecule is stored in cells, with a large portion of it being stored in skeletal muscle.
A dietary high-carbohydrate diet can enhance protein synthesis and reduce the loss of muscle mass during disuse. This effect is attributed to the glycemic index of a food and its ability to increase the rate of protein synthesis during the recovery period from exercise.
Glucose is the preferred energy source of most cells, and can be converted to acetyl-CoA for oxidation to adenosine triphosphate (ATP), an important building block of cellular energy. The ATP produced by this process is used to drive many of the metabolic reactions that maintain muscle mass, such as those that synthesize amino acids and fatty acids.
Omega-3 Fatty Acids
Omega 3 polyunsaturated fatty acids (the 'o' in 'o-3' refers to the position of the first double bond in their chemical structure) have long been known to promote healthy wellbeing. They're thought to help keep the brain functioning well, preventing depression and dementia. They're also thought to improve cardiovascular health, reducing blood pressure and lowering bad cholesterol. However, more recently it has been found that o-3 fatty acids are important for maintaining muscle mass and strength.
Specifically, the long chain omega-3 fatty acids eicosapentaenoic acid (EPA; 20:5 n-3) and docosahexaenoic acid (DHA; 22:6 n-3) are known to stimulate muscle protein synthesis, reduce inflammation, and improve exercise recovery. These effects are mainly due to their anti-inflammatory properties, which are particularly beneficial after strenuous exercise and can protect muscles from damage.
This is probably the primary reason why many athletes find that o-3 fatty acids increase their ability to train harder and more often, and help them recover quicker from intense training sessions. In fact, research has shown that o-3 fatty acid supplementation increases muscle protein synthesis by about 20%, which is more than enough to promote muscle growth. It is also believed that these fatty acids can reduce delayed onset muscle soreness, which usually occurs one to several days after a strenuous exercise session and is thought to be related to microscopic muscle tears and increased inflammatory response.
Omega-3 fats are an integral part of cell membranes and affect how receptors function, so they have a wide range of benefits. They can reduce the risk of heart disease by decreasing blood triglycerides and clotting, contracting and relaxing artery walls, and reducing inflammation. They can also benefit the brain, optimizing neuron function and boosting production of the feel-good hormone serotonin. The body can get omega-3s from eating fatty fish, but the best source of the long-chain omega-3s EPA and DHA is from algae oil. This is why the o-3s are often called marine omega-3s.
Carnitine benefits athletes and bodybuilders because it aids energy production, enhances endurance, prevents muscle damage, amplifies fat-burning and boosts brain function. It also helps maintain healthy blood sugar levels. Carnitine is naturally produced in the human body and can be found in red meat, dairy products and beans. However, for those who don’t eat these foods, taking carnitine supplements is an option. One study out of Turkey, published in the Journal of Strength and Conditioning Research, showed that giving professional soccer players three to four grams of carnitine before training boosted their endurance and lengthened the time it took them to reach exhaustion.
L-carnitine is an antioxidant, which means it counteracts damaging free radicals that are produced during exercise and metabolism. When free radicals are present in the body, they can damage lipids, proteins and even DNA, which contributes to cell death and muscle wasting. Carnitine’s role as an antioxidant reduces oxidative stress and improves protein synthesis, which slows muscle wasting and enhances recovery from exercise.
Some studies have shown that acetyl-L-carnitine, which is another form of carnitine, may improve mental capacity and delay the onset of Alzheimer’s Disease, a progressive memory loss condition. However, more extensive studies are needed to verify these results.
Several studies have found that carnitine decreases symptoms of chronic fatigue in people with cancer and other conditions. Cancer-related fatigue is common in patients receiving chemotherapy and radiation treatments and can impact quality of life. Several studies have found that carnitine or acetyl-L-carnitine can decrease fatigue in these patients.
In addition, a randomized controlled trial in 58 frail older adults who were identified as pre-frail found that those supplementing with L-carnitine had lower Frailty Index scores and improved hand grip test results than a placebo group.
ALCAR, a newer form of carnitine, has been shown to significantly reduce blood ammonium concentration in people with liver cirrhosis, improving their quality of life and reducing symptoms of both subclinical and overt hepatic encephalopathy. However, more clinical trials are needed to determine whether this form of carnitine has the same effect on those without hepatic cirrhosis.
Skeletal muscle tissue is continuously remodeled via the simultaneous metabolic processes of muscle protein synthesis (MPS) and protein degradation. This process degrades old and damaged muscle proteins and re-synthesizes new, more functional muscle proteins to maintain skeletal muscle mass and quality. Multiple nutrients including whey protein, creatine, arginine, and the amino acid glutamine have been shown to enhance muscle hypertrophy and prevent sarcopenia through their effects on MPS and/or protein turnover in resistance-trained athletes.
However, it is important to note that uncomplicated muscle disuse atrophy in humans is often accompanied by a decline in the stimulation of MPS by ingested dietary protein, which is known as "anabolic resistance."
Recent studies have demonstrated that supplementation with eicosapentaenoic acid and docosahexaenoic acid (O3FA) may mitigate a reduction in both the magnitude of the loss of muscle mass and the associated decrease in strength during simulated muscle disuse. This protection was attributed to an increase in the responsiveness of MPS to ingested protein in O3FA-supplemented muscles and preservation of thiol groups in oxidatively stressed muscle cells to prevent oxidative damage.
The most effective way to combat muscle atrophy and sarcopenia is through regular exercise, particularly with resistance training. Optimizing muscle mass improves strength, functionality and quality of life, especially with advancing age. While doctors have long warned of the loss of bone mass (osteoporosis) that accompanies aging, far less attention has been paid to the debilitating loss of muscle mass (sarcopenia). With a well-rounded regimen of dietary modification, hormone replacement therapy as indicated, nutritional supplements and vigorous resistance exercise, it is possible to significantly improve muscle mass and function even into advanced age.