Very low protein diet — Good for health?
Originally Published: October 11, 1996 - Last Updated / Reviewed On: March 14, 2008
What are the consequences to having a diet too low in protein?
Protein certainly has been a hot topic in the news lately. A lot of confusion exists as to how much protein we really need.
For the general healthy population, numerous studies have found that we require 0.8 grams of protein per kilogram of body weight, or a little over 7 grams of protein per 20 pounds. (Athletes require a bit more — 1.0 g/kg, or about 9 g per 20 pounds — to help increase and/or maintain muscle mass). For example, a person who weighs 150 pounds or 68.2 kilograms would need about 55 (68.2 x 0.8) grams – almost 2 ounces — of protein per day. This varies from individual to individual depending on her/his amount of lean body mass.
Our bodies need protein for numerous functions. Hemoglobin, which carries oxygen, is an essential protein that gives blood its red color when oxygenated. Antibodies, which act as defenders against disease, are composed of proteins. Hormones, some of which are made from amino acids (the building blocks of protein), regulate many systems in our bodies. These include the regulation of metabolism, digestion, and nutrient absorption, and the concentration of blood glucose. Proteins are also used by our cells to regulate the distribution of water and the movement of nutrients in and out of cells, particularly since proteins are one of the components of cell membranes. Furthermore, proteins are involved in blood clotting, acid-base balance, and visual pigmentation.
Considering we need protein to help our bodies carry out and sustain essential physiological functions, a diet very low in protein is obviously not a good idea. If your diet is insufficient in protein, you could also be deficient in many important vitamins and minerals found in protein-rich foods. Deficiencies could occur in niacin, thiamin, riboflavin, B-12, B-6, iron, zinc, and calcium, among others, depending on what foods are missing from your diet. The effects of prolonged low protein in the diet would eventually manifest themselves as impaired immune function, and irregularities in other bodily functions and systems described above.
As you can see, proteins are an integral and necessary part of our functioning. The good news is that it is not difficult to obtain sufficient protein from our diet. Dietary protein can be obtained from animal and vegetable sources. Animal sources, such as meat, fish, poultry, eggs, and dairy products, contain complete proteins — all the amino acids our bodies require to form the proteins we need. Vegetable sources, such as nuts, seeds, legumes (beans, peas, lentils, and soy products), grains (breads and cereals), and green leafy vegetables, contain incomplete proteins. This means that not all of the amino acids are found in one food. Mother Nature is tricky — the amino acids absent in some foods are present in others. Rice and beans, which together have all the essential amino acids, form a complete protein. This is an example of a way vegetarians can make sure they get complete proteins from their diet.
The following is a broad overview of the protein content in different food groups:
|1 cup milk||8 g|
|3 oz. lean beef, fish, or poultry||21 g|
|1/2 cup beans||7 g|
|1 slice of bread||3 g|
|1/2 cup cooked vegetables||2 g|
Dietary protein adds up rather quickly, and without too much effort. In the US, it is rare to find protein deficiencies among the general population. Ours is more a problem of excess than deficiency.
If you have special dietary needs and/or would like some nutrition counseling to help you eat enough protein from your diet, talking with a nutritionist can be a big help. Columbia students can use Open Communicator or call x4-2284 to make an appointment.