Consuming sensible protein foods and a variety of them, whether it is animal-based protein or plant-based protein, is essential to a healthy and nutritious diet.
Discovered in the 1800's by a chemist named Mulder, proteins are the most researched biological molecules even today. The human body contains around 50,000 different proteins, each having its own unique, critical functions.
Proteins are made up of building blocks called Amino Acids. There are 20 different amino acids that human beings need. Of these, 9 fall under the essential category. ‘Essential’ refers to a category of nutrients that we need, which the body is not capable of making – and therefore such nutrients have to be derived from the foods we consume. Food that contains all 9 essential amino acids is called a ‘complete’ protein. Complete protein is required for growth and normal body tissue maintenance. Foods that contain only some of the essential proteins are termed ‘incomplete’. These support normal maintenance of tissue but not growth.
Amino acids are made up of 4 basic elements: Carbon, Hydrogen, Oxygen and Nitrogen. These are linked together in different ways with other side elements or molecules to give each acid its unique character and function. Amino acids are also the products of protein digestion by our gut. They are absorbed into the blood stream and form an ‘amino acid pool’ which is like a bank account from which the body draws whatever it needs to reconstruct different types of proteins.
Proteins after being absorbed from food, last for just 3 to 5 hours. We have to keep replenishing this stock on a daily basis for which we need to eat different types of protein foods.
The body works fast to utilise these amino acids within this short time. If there is an additional demand due to moderate physical activity, the body steps up protein production and increases its storage in our muscles. Building of muscle mass (lean body mass) is a desirable process. On the other hand, excess protein not used by the body is converted to fat and stored for energy use.
Benefits of Protein
- Help in all body-related processes from formation of skin, hair and nails, to making sure that each cell in your body receives a supply of oxygen.
- Essential to build and repair body tissue and to maintain cell growth.
- Makes up hormones, enzymes, genetic material, blood, bone marrow and the list goes on.
- Necessary when growth takes place - during childhood, adolescence, pregnancy and lactation.
- Provides additional energy when there is insufficient carbohydrate and fat intake. However, fats and carbohydrates cannot replace proteins since they do not facilitate cell repair and growth.
Hence it is very important to consume a variety of proteins daily to constantly replace and repair cells and tissues in the body. Infancy, childhood and adolescence are high-growth phases during which protein plays a huge role. If there is any consistent deficit in dietary protein intake during these times, the consequences can last a lifetime! In extreme protein deficiency, the respiratory system and heart muscles are weakened - this is seen mostly in children from impoverished families.
Foods in the protein group
Proteins can be obtained either from animals sources or plant sources.
Animal protein: Animal products such as eggs, milk, fish, cheese and lean meat are a source of complete protein. Animal protein is also more easily absorbed by the body.
To stay healthy, parents have to be very selective about animal protein. This discrimination is important because meat, eggs and milk/milk foods are bundled with saturated fats and bad cholesterol, though they may be labelled as more ‘complete’ protein foods. But eating 8 ounces per week of seafood may help reduce the risk for heart disease because there are omega-3 fatty acids found in varying amounts in seafood.
Plant protein: Most plant food proteins, on the other hand, are classified as incomplete proteins because one or more essential amino acids are missing in them. To get the benefits of all the essential amino acids, it is best to eat a mix of protein foods. High protein plant foods include dals, pulses, legumes, sprouts, channa dal, rajma, nuts, seeds. Green leafy veggies like curry leaves, drumstick leaves and black nightshade also contain protein, but you need to consume large quantities of these to get the protein benefit.
Cereal grains like oats, whole wheat and whole rice are good protein sources. Refining of cereal grains (white rice / maida), as is the tendency here, can result in at least 18-25% loss of valuable protein from the grain.
Other high protein sources now popular are soybeans, tofu (made from soybeans), soymilk and quinoa (originally from South America). Certain nuts, soybeans and the germ of grains are also complete proteins.
- Keep your protein food lean
- Trim away all of the visible fat from meats and poultry before cooking.
- Broil, grill, roast, poach, or boil meat, poultry, or fish instead of frying.
- Drain off any fat that appears during cooking.
- Skip or limit the breading on meat, poultry, or fish. Breading adds calories. It will also cause the food to soak up more fat during frying.
- Prepare dals and pulses without added fats.
- Choose and prepare foods without high fat sauces or curries.
- Stick to low fat milk/milk products.
Variety is the spice of life
One should remember that essential amino acids are not equally distributed in any protein food, animal or plant based. The concentration levels of amino acids differ in different foods. Hence, to ensure that the body gets all the essential amino acids, it is important to have a variety of foods by combining plant and animal foods or by combining plant proteins from a variety of cereals and grains.
For example, according to uen.org, peanut butter lacks 3 amino acids. By spreading it on buttered whole wheat (not white) bread and serving it with a glass of milk or some yogurt, it becomes a complete protein.
Avoid protein supplements
Protein supplements need to be prescribed by a doctor or recommended by a nutritionist, only under specific circumstances – for endurance athletes, undernourished children, people suffering from chronic disease, injury, infection or diabetes. Avoid taking proteins beyond what is prescribed, as processed foods have their own disadvantages.
If your family eats all the foods recommended daily in the chart and at least 1 or 2 servings of foods recommended weekly, each member will be getting around 70 g of protein or more per day, which is more than sufficient. Besides, a little more comes from the intake of vegetables.
Smitha Suresh is a Chennai-based nutritionist.