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March 21, 2010
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How Much Protein Do You Need?
Robert M. Russell, M.D., and Carmen Castanada Sceppa, M.D., Ph.D.
Carmen Castanada Sceppa, M.D, Ph.D., is a scientist working at the Jean Mayer USDA/Human Nutrition Research Center on Aging at Tufts University School of Medicine. Carmen's research emphasizes protein nutrition and physiological function of healthy older individuals and those with chronic illnesses.
RMR
How does the average intake in the United States measure up against the Recommended Dietary Allowance (RDA) for protein?
CCS
The typical American diet provides plenty of protein — more than the RDA in most instances. The RDA represents the minimum amount of protein needed to fulfill protein needs in 97.5% of the population. This value is equal to 0.8 g of protein per kg body weight per day. The average mixed American diet provides from one to two times the RDA for protein. You might think, then, based on this that protein deficiency is unlikely in the U.S. . However, the RDA for protein has been derived from research studies performed on healthy individuals. Growing children, pregnant and lactating women, the elderly, and anyone undergoing severe stress (trauma, hospitalization, surgery), disease or disability need more protein.
RMR
What if you exercise?
CCS
We have seen in our lab that individuals undergoing endurance training increase their protein needs to about 1 to 1.2 g per kg per day, well above the RDA. In contrast, for subjects performing resistance exercises or weight lifting, the RDA for protein seems to be adequate. In resistance training, you are building up muscle and protein is used more efficiently.
Muscles are built from protein. Unlike fat cells for fat and muscle or liver for glucose, there is no place in the body to store protein. We need to consume enough protein to allow our muscles to be healthy and perform work. RMR
Carmen, we hear a lot in the media about balancing different types of proteins. What are the best sources of protein and what exactly is meant by complementary proteins?
CCS
Animal and plant or vegetable foods are the two major protein sources. Animal protein foods include meat, poultry, fish, dairy products and eggs and are said to be of high biological value. That is, they contain all nine essential amino acids that can not be synthesized in the body (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine).
Plant protein sources, although good for certain essential amino acids, do not always offer all nine essential amino acids in a single given food. For example, legumes lack methionine, while grains lack lysine. What is needed are complementary proteins, various protein food sources that, eaten together, enable a person to meet the standards of a high biologic protein diet. RMR
Do vegetarians and people on macrobiotic diets get into problems with protein malnutrition?
CCS
There are two types of vegetarians. Lacto-ovo vegetarians and strict vegetarians or "vegans". Lacto vegetarians eat animal protein of high biological value, eggs and dairy products. Vegans, however, eat a more limited diet and often must take amino acids supplements to make up for their not-so-high biological protein diet. If vegans eat a variety of plant foods — cereals, nuts, seeds, grains and legumes — they'll be fine. They don't have to eat all these food items at a given meal. However, they should consume most or all of them during the course of the day to insure a well balanced protein diet of high biological value.
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Comment by: sondra
Thu., Mar. 18, 2010 at 11:05 pm EDT thank so much for all the help
Comment by: Giles
Sun., Mar. 7, 2010 at 5:15 pm EST GOod work, Robert and all. GC I love it. GC
Comment by: inetryconydot
(Canada)
Sat., Mar. 6, 2010 at 5:11 am EST Some may feel squeamish about eating it, but rabbit has a fan base that grows as cooks discover how easy they are to raise — and how good the meat tastes.
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(United Kingdom)
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Comment by: Kida
Tue., Feb. 23, 2010 at 8:07 am EST Can You put answers for kids please.!!
Comment by: ged
Sat., Feb. 20, 2010 at 4:02 am EST in nutritional view point, which is better, animal protein or plant protein?
Comment by: Ashok
Tue., Feb. 16, 2010 at 1:15 am EST very good Ashok
Comment by: alvaro
Fri., Feb. 12, 2010 at 11:08 am EST you said that we need to consume enough protein to allow our muscles to be healthy. However,how much porcentage of protein as a energy source muscles need comparing to triglycerids and glycogen as another type of energy that they also use?
Comment by: Anonymous
Tue., Feb. 9, 2010 at 12:03 am EST Is 200g of canned tuna for lunch too much protein? I am trying to lose weight
Comment by: DR.KRISHNAIAH GOUD
Sat., Jan. 30, 2010 at 1:30 am EST sufficient information available
Comment by: Fiaz Hussain
Mon., Jan. 25, 2010 at 2:44 am EST i want to information abot the bak pane during the waight lifting and start leg pane and after going int under the pens right said bolse thanks
Comment by: james
Thu., Jan. 7, 2010 at 11:41 am EST so is that enough protein? i mean this is computed right right? cuz when you work out to thin down you also burn your protein into energy so its not actually used by the muscles just for energy so it becomes waste, well not really but does this computation considers that?
Comment by: Chucky B
Wed., Jan. 6, 2010 at 4:51 pm EST Someone who is weight training doesn't need any more protein than .36g / lb of body weight, the RDA? How could that possibly be? That flies in the face of umpteen studies on the subject over the years.
Comment by: Griner
Sun., Jan. 3, 2010 at 8:37 pm EST I have just started my journey as a vegetarian (not vegan) and now I have concerns about not receiving enough protein. I will continue to eat biological products such as eggs and milk, but unsure if this is enough. Is there something I can do to add to my protein intake or should I reconsider a vegeterian lifestyle? |
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