All scientific studies confirm it: lack of exercise and inadequate nutrition cause muscle wasting, which leads to frailty, illness and poor life quality.
The key to prevent “getting old” is to exercise regularly and eat the right amount of “good quality” protein. But what is good quality protein and how much should we eat?
Proteins are the only food source that deliver Nitrogen and essential amino-acids to our body, which are needed for muscle maintenance and many other functions. But, unlike glycogen or fat, proteins cannot be stored as a reserve in our body. This means that the full spectrum including all essential amino-acids must be available when the body needs to maintain or repair a muscle, or any other structure for that matter. If one of the amino-acids is missing, the body has no other choice than to break down muscle elsewhere to obtain the necessary building blocks.
That is why the quality of the protein we eat is so important: it must include all the essential amino-acid. To avoid losing muscle and gradually becoming weaker, also the timing and the amount of protein we eat matters. Muscle wasting becomes a progressively worse problem with age, but science reveals that it can be prevented and even reversed with the right diet and exercise schedule.
Quality of protein
The composition of a protein and the contents of essential amino-acids (it´s biological value) is the main factor that determines it´s quality, but also the digestibility needs to be considered, and even the cooking method can change the quality. The latest most accurate standard that is used to measure the quality of a protein is its Digestible Indispensable Amino Acid Score (DIAAS), which considers both the biological value and the amount that is absorbed by the body.
Animal sources of protein are better digested than plant-based proteins. Boiling or frying food can increase its digestibility because it disrupts the structure and exposes the amino-acids better to digestive enzymes and absorption. Prolonged extreme heat, however, will lower the nutritional value of the protein. Hydrolyzed protein powders have been processed so that they are already cut up into small pieces. This increases the digestibility and therefore the availability of amino-acids for the body: the higher the degree of hydrolysis, the higher the quality of the protein and its efficiency for muscle synthesis.
Supplements of pure essential amino-acids are scoring even better on nutritional level because they are completely available for absorption and, once inside the body, directly usable for muscle building.
Quantity of protein
Protein recommendations, as set by government institutions, are given as the “lowest level” of protein intake that is needed to prevent disease in healthy adults. According to latest research, this amount is not high enough for individuals that are very active, nor for the ageing population. Older people need to consume far more proteins because they exhibit “anabolic resistance”. The capacity of the muscles to be stimulated for growth diminishes, due to dropping hormone levels and increased inflammation. Therefore, more stimulation is needed to keep the muscles in shape.
In Europe, it is recommended to consume 0,80 grams of protein per kg of body weight per day, but these recommendations make no difference between an 18 year old and a 60 year old adult. To prevent gradual muscle loss, elderly adults must consume between 1,2 and 2 grams of protein per kg body weight per day, as shown by the latest scientific research. This means that an 80 kg ageing man should consume at least 96 grams and maximum 160 grams of protein per day. Because our basic metabolic rate slows down with age, older people need less calories than younger people to avoid obesity. With conventional meals it is very difficult to double on protein intake but reduce calories. Therefore, protein shakes or supplements of essential amino-acids supplements offer the ideal solution to obtain an extra amount of proteins without adding an excess of calories.
Scientific studies have shown that a protein amount of 20 g or 10 g of essential amino-acids that is taken as a supplement every day, increases the muscle protein synthesis rate by 75 % in young healthy individuals. For older individuals that amount needs to be doubled to reach a similar muscle protein synthesis rate.
Distribution of meals throughout the day
It is extremely important to divide protein over several meals a day. Scientists recommend to include in each meal an amount of at least 0,4 gram per kg body weight, and not leave more than 5 hours in between meals. To prevent muscle-wasting, an additional post-exercise and/or pre-sleep protein supplement will supply the rest of what is needed to stimulate the anabolic response. A single dose of 20 to 40 g of protein prior to sleep is properly digested and the amino-acids are found to be correctly absorbed, without affecting sleep quality or next morning appetite. The myth that you should not eat before bed because the food will not digest and it affects your sleep is incorrect, at least when it is pure hydrolyzed protein or essential amino-acids that are consumed. A protein supplement before sleep does not have negative effects on fat metabolism or energy expenditure.
A diet that is high in protein needs an increased amount of vitamin B1, but actually all of the B vitamins are necessary for energy metabolism. Vitamins and minerals act as cofactors for enzymatic reaction: many enzymes that perform anabolic reactions depend on the collaboration of these cofactors, and do not function without them. Deficiency of one type of vitamin can cause inability for the muscle to grow. Also, supplements that deal with inflammation, anti-oxidants, other vitamins and omega-3, are needed to prevent muscle breakdown. Therefore, eating a balanced diet, with lots of fresh vegetables and fruit is just as important as the protein itself.
To preserve muscle mass, physical activity is equally important as good nutrition. Scientific research has determined that it is particularly “strength targeted” exercise with weights that is needed to stimulate muscle synthesis. It has a direct effect on muscle mass and health, but also an indirect effect because it increases the utilization of the dietary protein and the anabolic response. Endurance activities, on the other hand, like walking or cycling, have little effect.
Scientific research suggests following recommendations to preserve muscle mass with age:
• Exercise 3 times a week, using both heavy loads and light loads.
• Eat every day at least 1,2 grams and maximum 2 grams of protein per kg of body weight.
• Throughout the day, distribute meals in equal portions of 0,4 grams of protein per kg of body weight.
• Take an extra supplement of 20 grams of protein powder, or 10 grams of essential amino-acids after exercise and/or before going to bed.
Dr. Sonia Van Kerckhoven
PhD in Cellular and Molecular Biology
MSc Expert in Nutrition
Expert in Medical Genetics