Proteins for Growth and Repair

All tissues and cells need protein. Proteins are very important for muscle building and keep hair, nails, skin and eyesight healthy. Proteins are used for transporting iron and oxygen in the blood and for the manufacturing of hormones, enzymes, stimulation of the immune system and other compounds that provide fuel for your body.

Proteins for Weight Loss

Protein is considered to be the most filling nutrient according to the energy it gives. Since protein stimulates the fat burning hormone, glucagon, protein is considered good for weight loss. 10-20% of your daily calorie intake should be from protein.

Proteins – Amino Acids

Proteins are converted in the body into 22 building blocks called amino acids and divided into complete and incomplete proteins.

  • Complete Proteins from Animal Foods: Complete proteins contain 9 of the 22 amino acids that are essential to life and must be added to the diet. They are found in animal foods like meat, fish, milk cheese and eggs. Vegans and vegetarians can get shortages of the essential amino acids lysine and threonine if they are not observant. Lysine can be found in soy beans, chickpeas, kidney and oats. Threonine can be found in lenses, cereal, herbs and grasses. To avoid shortage it is easier if you drink milk, otherwise you must make sure that you eat various kinds of beans, lentils etc.
  • Incomplete Proteins from Plant Foods: Incomplete proteins contain the remaining 13 of the 22 amino acids and can be found in vegetables, cereals, soybeans, dry beans, peas and peanuts.

Protein Deficiency

Protein deficiency is relatively rare in developed countries but people who are on a strict diet can be at risk. Symptoms of protein deficiency can be decreased muscle mass, fatigue, anemia, impaired immune function, decreased metabolism, reduced fertility, hair loss, premature aging, mood swings and memory problems.

Excess Protein

Too much protein can harm your body. If you eat too much protein the excess will be stored as body fat. Over-consumption of protein can also cause constipation, diarrhea, excessive gas, dehydration, dizziness and bad breath.

Protein Intake Recommendation

The recommended daily allowances (RDA) set by the Food and Nutrition Board, is 0.36 grams of protein for every pound of body weight.

Dietary Reference Intakes (DRIs) – Estimated Average Requirements for Groups:

Life Stage GroupProtein Grams per Day
Children 1-3 years11
Children 4-8 years15
Males 9-13 years27
Males14-18 years44
Males 19-30 years46
Males 31-50 years46
Males 51-70 years46
Males > 70 years46
Females 9-13 years28
Females 14-18 years38
Females 19-30 years38
Females 31-50 years38
Females 51-70 years38
Females > 70 years38
Pregnancy 14-18 years50
Pregnancy19-30 years50
Pregnancy 31-50 years50
Lactation 14-18 years60
Lactation 19-30 years60
Lactation 31-50 years60

Source: Food and Nutrition Board, Institute of Medicine, National Academies