Very low protein diet — Good for health?

Originally Published: October 11, 1996 - Last Updated / Reviewed On: July 19, 2013
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Dear Alice,

What are the consequences to having a diet too low in protein?

—SMS

Dear SMS,

Beans, seafood, poultry, meat, and eggs. These are just a few sources for protein. 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. The good news is that it is not difficult to obtain sufficient protein from our diet and most Americans have no trouble doing so. Dietary protein can be obtained from animal and vegetable sources. 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.

The Recommended Dietary Allowances (RDA) for protein are as follows:


Recommended Dietary Allowance for Protein
  Grams of protein needed each day
Children ages 1 - 3 13
Children ages 4 - 8 19
Children ages 9 - 13 34
Girls ages 14 - 18 46
Boys ages 14 - 18 52
Women ages 19 - 70+ 46
Men ages 19 - 70+ 56

Table via the Centers for Disease Control and Prevention

Protein recommendations vary from individual to individual depending on her/his amount of lean body mass.

As you can see, proteins are an integral and necessary part of our functioning.  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; however, according to research, it's not necessary to get complete proteins for every meal. Having some amino acids during breakfast and the others during lunch will have the same effect as consuming them together, during the same meal. Your body has the ability to combine complementary proteins as long as their eaten on the same day.

The following is a broad overview of the protein content in different food groups:

1 cup dairy or soy milk 6-8 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, as mentioned earlier, 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 on the Morningside campus can use Open Communicator or call 212-854-7426 to make an appointment. Students on the CUMC campus can contact Medical Services at 212-305-3400.

Alice

February 4, 2014

550964
Not hard to get enough protein, even if Vegan, if you know how to eat. I find not good, those who eat all raw veggies and fruits, you need some grains and definitely proteins. But many seeds, root...
Not hard to get enough protein, even if Vegan, if you know how to eat. I find not good, those who eat all raw veggies and fruits, you need some grains and definitely proteins. But many seeds, root crops and nuts, have far more protein then meat or animal products like dairy and eggs. I don't eat any animal products, plus no wheat/gluten grains, and nightshade plants, they cause inflammation in my body, I am intolerant of them; some due I due to auto immune problems, and somewhat I think because of my Native American heritage. As was said already, you don't have to consume a full amino acid spectrum at each meal, just accomplish it during the day. You actually get more complete digestion of things, if you have less combinations of of food groups. Proteins best digested if eaten alone or only with other proteins, veggies ok, if not starchy or too starchy. Most fruits don't digest well with starches, but acid fruits help digest proteins. I find that some fruits like Melons, are best eaten by themselves, nothing else added; eat fresh fruits that way. I sometimes eat things like dates and nuts together, that seems ok.

March 11, 2013

525286
Great article, Alice. I'm currently studying the effects of a body building diet on a "minimal" amount of protein, vs the 1.5-2.0 grams p/ body weight that is so popular these days. I'm curious...
Great article, Alice. I'm currently studying the effects of a body building diet on a "minimal" amount of protein, vs the 1.5-2.0 grams p/ body weight that is so popular these days. I'm curious about the possible positive effects of lessening the protein load, if only for a short time. As you stated, our problem is that of protein excess. Thanks for a great advice.