Three nutrients that produce energy

“I answer 20,000 letters a year and many couples have problems because they don’t get adequate protein and vitamins.”

Barbara Cartland, English novelist.

The Observer (London) “Sayings of the week” (August 31, 1986).

There are three nutrients that produce energy: carbohydrates, protein, and fat. These nutrients are written on the following lines.

1. Carbohydrates. Carbohydrates generally provide most of the energy in a normal diet, but no single carbohydrate is an essential nutrient in the sense that the body needs it but cannot produce it on its own from other nutrients. If your carb intake is less than 100g per day, ketosis is likely to occur.

2. Fats. Due to their high caloric value, fats are useful for people with a high energy expenditure; Furthermore, they are useful for cooking and making food appetizing. Although rats require linoleic or arachidonic acids in their diet, essential fatty acid deficiency is rare in man. It has been shown in patients who have been fed intravenously for long periods without fat emulsions. They develop a desquamative dermatitis, and eicosatrienoic acid accumulates in plasma lipids. Essential fatty acids are precursors for the synthesis of prostaglandins.

3. Protein. Proteins provide about 20 amino acids, eight of which are essential for normal protein synthesis and for maintaining nitrogen balance in adults. These essential amino acids are methionine, lysine, tryptophan, phenylalanine, leucine, isoleucine, threonine, and valine. Histidine and perhaps arginine are also necessary for growing babies.

The ‘biological value’ of different proteins depends on the relative proportions of essential amino acids they contain. Animal-based proteins, particularly from eggs, milk, and meat, are generally of higher biological value than plant-based proteins that are deficient in one or more of the essential amino acids. However, it is possible to have a diet of mixed vegetable proteins with high biological value if the principle of supplementation is used. For example, grains, such as wheat, contain about 10% protein and are relatively deficient in lysine. Vegetables contain around 20% protein which is relatively deficient in methionine. If you mix (or eat) two parts of wheat with one part of vegetables, you get a food that contains 13% of a protein of high biological value. This happens because the cereals contain enough methionine and the vegetables enough lysine to complement the other component of the mixture.

The usual amount recommended for adequate protein intake is 10% of total calories, that is, about 65 g for an average adult. The minimum requirement is less than 40 g per day of protein of good biological value for an adult.