Search Ask the Dietitian



Protein & Amino Acids


  1. Your information regarding protein requirements for weight training is being debated. Answer
  2. Is there any medical research or articles to back this recommendation to take whey? Answer
  3. When I enter 35% for my protein intake in your calculator, I get an error message that 35% is too high. I am a weight lifter. Answer
  4. I don't know how to tell what amino acids I get from what I eat. Answer
  5. Some references are saying that diets rich in animal proteins promote excessive elimination of calcium in the urine. Can you provide references? Answer
  6. Is milk a complete protein. Do I need to compliment milk and egg to make a complete protein? Answer
  7. To sugest that a male weight lifter needs only 63 grams of protein per day reminds me of my high school football days. Answer
  8. What are the benefits and problems associated with amino acid supplements? Answer
  9. In a well balanced 1500 calorie a day diet what is too much protein to consume? Answer


  10. Will the overdose of protein be harmful to a normal body function or is it simply not recommended? Answer
  11. Does hard boiling an egg destroy some of the amino acids or does it remain the same as raw? Answer
  12. What's the difference between powdered protein supplements such as whey and amino acid pills? Answer
  13. How much protein do I really need per day in grams? I am female, mid 30's. Answer


I just wanted to let you know that your information regarding protein requirements for weight training is being debated on the news groups called misc.fitness.weights. The title of the debate is "MetRx Protein Debate". I'm speaking of your protein topic.

I'm hoping that you will join the discussion and contribute with some empirical data, as most of what is submitted is anecdotal comments. As I'm sure you already know, these hyper-protein consumption views are held very staunchly by body builders and suggesting evidence to the contrary has to be done very tactfully. So, if you want a challenge (and an interesting experience), please drop by news group. Thanks.

I have worked with body builders before at the university where I taught. You and a few others seem to be responding appropriately to the excessive protein believers. I read a few of the messages and unfortunately, some body builders just don't listen to research and would rather listen to testimonials. I report research findings not testimonials. I focus on people who want valid info to make lifestyle changes, not supplement pushers.

Suggest people on the newsgroup read "The Homocysteine Revolution" by Dr Kilmer McCaulley. Thirty years ago, he compiled the research on homocysteine (an amino acid) that is an intermediary in the breakdown of methionine (an amino acid). Homocysteine appears cause and advance arteriosclerosis (hardening of the arteries) as a result of high protein diets (which would include food and amino acid supplements). It appears that vitamin B6, folacin (folic acid) and vitamin B12 help reduce homocysteine. However, this is not a case of have your high protein and eat your vitamin supplements too.

Tell the newsgroup to read this.


I saw a patient who is taking whey as powder in shakes and creatine, and other amino acid supplement to define his muscle. These supplements are very expensive as you know. I discourage him from doing this, but I wondered if there was any medical research or articles of any kind to back this recommendation up. This patient is 6 feet tall and weighs only 160 pounds. His diet is deficient in calories which I already told him and gave him Nancy Clark sports info. Thanks for your help!

Whey is the clear liquid that is left after cheese curds are removed during cheese making. It is often dried and used as an ingredient in other foods. Whey contains lactose, milk solids and protein. Hope this athlete isn't lactose intolerant.

Weight lifters or body builders who want to cut muscle (show defined muscles in competitions) often get sucked into taking protein or amino acid supplements. These supplements do not build muscle and combined with an already high protein intake, often stress their kidney function. You mention that this athlete is deficient in calories. If so, then he is burning protein as a very expensive fuel. Unfortunately, weight lifters and body builders sometimes don't listen to reasonable nutrition advice while looking for the quick fix. Nancy Clark is an excellent source of sports nutrition information.

Has he tried my Healthy Body Calculator? It will predict a healthy weight, even for lean athletes as well as a personalized Nutrition Facts report based on their nutritional goals i.e. % of calories from fat, protein and carb as well as weight change.

If you are a member of the Academy, you can join an electronic mailing list (EML) for any of the dietetic practice groups that you paid with your Academy dues. I will forward a message to you about joining Academy electronic mailing lists (EML). There have been many discussions about creatinine and other protein supplements athletes take. I think you would find it beneficial if you are a member of the Academy. If you are not a member of the Academy, you will not be allowed to join.


When I enter 35% for my protein intake in your Healthy Body Calculator, I get an error message that 35% is too high. I am a weight lifter and this is not 'unreasonable'. Please fix this or find a way to enter whatever values we would like. I like your page and would like to keep using it.

Actually, protein intakes above 20% are not recommended based on current research, even for weight lifters. High protein intakes stress your kidneys and do not result in greater muscle gain.


I exercise frequently, so I try to eat a diet rich in amino acids. Unfortunately, I don't really know how to tell what amino acids (or how much of them) I get from what I eat. Since food labels don't give us this information, is there another way to find out?

First you need to write down everything you eat. Then your choices are to either send your food records to a registered dietitian who could analyze the amino acid content in the foods you eat or find a nutrition software package that has amino acid content of foods in their database.

A dietitian's report could include the levels of 9 essential amino acids in your foods including histidine, which is essential only for children. Their report also graphs your food plus any amino acid supplements you may take so you can see the combined effect. A dietitian could also include the amounts of non-essential amino acids you eat. Remember that non-essential amino acids are still necessary to the body, but that your body can manufacture non-essential amino acids from essential amino acids.

Your other choice is a nutrition software package. Look for software that contains a database of amino acid content in food. There are very few nutrition software packages that contain amino acid food values though. Those that do are designed for nutrition professionals and are usually not available to consumers.


Some references are saying that diets rich in animal proteins stimulate the release of parathyroid hormone and promote excessive elimination of calcium in the urine, which encourages bone resorption."

One reference indicated that the federal government, intending to be on the safe side, established its minimum Recommended Dietary Allowances for protein at twice the value which it had determined as the minimum required for every person who participated in a federally sponsored experimental study. The reference pointed out that the average American routinely eats four times more protein than that in their daily meals. According to that, then, the average American actually consumes eight times more protein per day than any person in the study needed to sustain good health. The link between excessive protein and calcium depletion was said to be so strong that taking supplemental calcium does NOT stem the daily calcium deficit -- it is only slowed a trifle. But it went on to say that reducing protein intake to a level near the RDA had a profound positive effect. It left the body with a daily net influx of calcium, even among older women who were not taking calcium supplements. Can you provide authoritative references to evidence that confirms or refutes this?

Have you read my calcium, Recommended Dietary Allowances and calories topics as the information about many of your questions can be found there? BTW, the average American only eats 15% protein and about 2095 calories per day which equates to about 79 grams of protein according to the most recent survey (NHanes III 1994) of US citizens by the government (Center for Disease Control). The RDA for protein is 63 gm for males and 50 gm for females. Therefore most American males eat 120% of their RDA for protein and American females 158%. Since nutrition surveys blend male and female data, these numbers may be reversed as males do tend to eat more protein than females.

By your sources, people would be eating over 200 grams of protein per day (RDA of protein for females of 50 times 4), which translates into 800 calories alone from fat free protein food sources i.e. no meat products. If this much protein were from lean meat sources, it would equate to an additional 1300 fat calories for a total of 2100 calories from protein sources alone. Based on the most resent government nutrition surveys, I don't think Americans eat that much nor do they only eat meat, though I do agree that they do eat too much protein.

Sorry, I cannot provide you with specific references as my nutrition information accumulates from many sources, but you can do your own research by doing a Medline (published medical research) search on-line. Search keywords such as calcium and protein or Recommended Dietary Allowances to find answers about many of your questions in the literature.


I've read the Q and A on milk, eggs and protein and still have a question. First is milk protein a complete protein?

Do I need to compliment milk protein and egg whites to make a complete protein?

Is the powdered egg white considered "raw" and therefore a problem with biotin?

I can't seem to find my answers anywhere, please help me. Please e-mail me with a response. Thank you.

Milk is a complete protein in that it has all 8 essential amino acids. Egg whites are a complete protein as well. No, you don't need to combine milk and eggs.

The powdered egg whites have to be heat treated to be dried and therefore are not raw nor will they destroy biotin.


Your attempts to give sound advice on sports nutrition are appreciated. However, it seems inappropriate that you give advice on matters, which are obviously outside the realm of your experience and expertise. To suggest that a male weight lifter needs only "63 grams of protein" per day reminds me of my high school football days, when the coaches wouldn't let us drink water on very hot days because it was "too hard on the body and we would cramp up.". That advice came from people who had the credentials to call themselves experts, also.

Questions:

1) What modern research can you point to that says protein needs don't increase with heavy muscle tissue breakdown? Modern research on sports nutrition I've seen indicates time and again that protein needs increase, often drastically, in weight training subjects. Otherwise, much less than optimal benefit is derived from that exercise, the body simply is not afforded the opportunity to rebuild itself quickly and adequately.

2) As opposed to quantity, what is the quality of the protein ingested? Incomplete proteins may be of little or no benefit to the athlete, as you are probably well aware, but your readers may not be.

3) Regarding the specific quantity of 63 grams: Does the weight lifter weigh 150 lb. or 300 lb.? To suggest so specific a number for ALL males, regardless of their biochemical individuality and weight variation and intensity of workout is beyond my comprehension.

4) For your future reference as a RD, MetRx is an engineered food formulated by Scott Connelly, MD. It was originally conceived in the context of helping patients in severely catabolic states (such as burn patients) to be able to retain lean body mass through aggressive nutritional intervention. Bodybuilders found out about the product and started using it with great success to build as quickly as possible. Dr. Connelly now markets the product for those who want to recompose their body's muscle-to-fat ratio. One serving has 37 grams of very high quality protein and only 260 calories.

I'm approaching 40, have lifted weights for 23 years now and have read every sort of hype from both the commercial and scholarly sides for almost as many years. I am extremely fit, maintain a very low body fat percentage and workout very hard, while recovering very quickly. One thing I've discovered from EXPERIENCE, regardless of what a few so called "experts" say, is that keeping lots of high quality protein in my gut throughout the day is the key I'd been looking for in maximizing my health and physique. And I am still looking for someone to show me any research that shows high protein intake damages normal and healthy kidneys and livers in humans. That's another one of those nutritional myths, repeated endlessly by the "experts.

Just last week, a teacher at the school here was arrogantly telling me that my diet was dangerous, that she had an MA in biochemistry. People standing around listening were snickering at her, because they could see what my body and posture looked like, as she was standing there, 40 lb. overweight and smoking a cigarette. The "expert."

The RDA for protein for adult males is 63 grams per day. Athletes can maintain protein equilibrium (muscle building equals muscle breakdown) on 1 gram of protein per kilogram of body weight per day. So take your weight, divide by 2.2 then multiply by 1. In fact most persons can achieve protein equilibrium (positive nitrogen balance) at 0.6 to 1.2 grams of protein per kilogram per day.

According to Dr. Carol Meredith at the University of California at Davis, muscle protein synthesis decreases during exercise and nearly doubles during recovery. Research she has shows that additional protein (studies of 1.35 grams of protein per kilogram of body weight per day) does not increase muscle mass or strength. In addition resistance exercise like weight lifting is a powerful anabolic (building) process that improves protein synthesis (increased muscle mass).

In fact what athletes need is increased caloric intake (60 calories per kilogram of body weight per day) which may contain protein food sources as well. One inherent problem with increasing protein from food sources, is you are probably also increasing fat content.

The supplement you are taking is 56% protein. Remember that your body can break down protein in food and break down muscle protein for energy if insufficient calories are consumed. So you may be burning expensive protein for fuel.

In regards to incomplete proteins, you are misinformed. If a person daily eats a variety of legumes (beans, peas, nuts), seeds, fruits, vegetables and grains, they will get all the amino acids an adult needs in sufficient quantity to supply all 8 essential amino acids. According to Dr. Peter Pellett at the University of Massachusetts at Amherst, the limiting amino acid is lysine, which would be a concern in persons eating only grains. I would suggest you read the vegetarian topic.

There is no food or supplement that will by itself convert fat to muscle as you indicate MetRx does all by itself. Otherwise, persons wanting to lose weight would have found instant success with it long ago. The only ways I know to lose body fat and replace it with muscle is through exercise, aerobic and weight training.

Burn patients lose lots of protein through the burn site which body builders do not. Body builder's protein losses are through sweat, urine and feces, the majority of which is not protein. When muscle is broken down during weight training, it frees amino acids into the blood which can then be recycled within the body unlike the burn patient whose protein loses are soaked up by gauze dressings. You are mixing apples and oranges.

There is lots of nutrition hype, most untrue in weight lifting and bodybuilding. While at the University of Minnesota, Duluth, I taught sports nutrition for several years, worked with college athletes, Olympic athletes and yes-competitive body builders. If you want nutrition expertise, ask a registered dietitian. Second, if you want exercise expertise, ask an exercise physiologist. Unfortunately your high school coach and the biochemistry teacher may not have the education and experience to provide "expert" nutrition advice. Think of the opportunity you missed with the biochemistry teacher to "teach" her what you have learned so that she could consider a more healthy lifestyle.

Lastly, remember that we are practicing nutrition like doctor's practice medicine. Nutrition science has changed even in the length of time I have been practicing. We don't have it perfect yet and recommendations like drinking water during exercise has changed over the years as a result of new research.

If you would like to read some good sports nutrition texts, try "The Athlete's Kitchen" by Nancy Clark MS RD or "Sports Nutrition" by Dan Benardot Ph.D., RD. Sports nutrition for children, try "Play Hard Eat Right" by Debbi Sowell Jennings MS RD and Suzanne Nelson Steen D.Sc. RD.


What are the benefits and problems associated with amino acid supplements, particularly a supplement with a wide variety of amino acids, for an individual on a heavy workout schedule and a high carbohydrate diet? I have heard that L-tryptophan supplements are associated with a blood disease, is this true?

Tryptophan is an essential amino acid when taken as a supplement can make a person sleepy. Turkey is high in tryptophan and do you remember how a turkey dinner makes people sleepy? Tryptophan is not associated with a blood disease.

Phenylalanine is another essential amino acid that isn't metabolized very well by children and adults with PKU. Is this the blood disease you were thinking of? PKU is genetically passed from parent to child.

There is no research to support any benefit to taking amino acid supplements for persons who exercise. Amino acids are either essential (8 can't be made by the body and must come from a source outside the body) or non-essential (12 that can be made within the body from essential amino acids). If you take an amino acid supplement, make sure it is contains only essential amino acids (isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine) or you are wasting your money. Amino acids eaten in crystalline form will be absorbed directly into the blood stream. Your body can only use so much protein and any excess is used for energy or stored as fat. Your body uses protein to build and repair lean tissue (muscles and organs).

Weight lifting will increase muscle size and the average US diet and the RDA contains enough protein (females 50 gm and males 63 gm per day) to promote an increase in muscle mass. Some weight lifters talk about lifting breaking down their muscles. Any movement of protein out of muscles will go into the blood pool of amino acids that is available to all lean tissue. Research has shown that the uptake of amino acids improves in weight lifters during recovery after exercise.

A healthy person does not loose significant protein other than through hair and nails. So the protein and amino acids you eat stay in your body.


In a well balanced 1500 calorie a day diet what is too much protein (in grams) to consume ? I am involved in weight training and really feel better when I eat MORE protein than is advised in various charts. Why is too much (assuming the protein I am eating is high quality, low fat, which it is) bad for you ? What harm does it cause ?

Protein should comprise 10 - 15% of a healthy diet. If you eat 1500 calories per day, then you should eat about 56 grams of protein. Take 1500 calories times 15%, then divide by 4 calories per gram. 1500 calories seems low for someone in a weight training program. Your calorie requirements may be as high as 60 calories per kilogram per day. Take your weight in pounds, divide by 2.2 and then multiply by 60 to get your calorie needs.

Protein once absorbed into the blood is filtered by the kidneys and if not used to build and repair muscle tissue, is converted to energy or stored as fat. At 1500 calories, I doubt though that any protein would be stored as fat. Protein requirements of athletes are 1.2 gram of protein per kilogram of body weight. Take your weight in pounds and divide by 2.2 to get your weight in kilograms, then multiply by 1.2 to get your protein needs. For instance a 154 pound person would weigh 70 kg and would need 84 grams of protein.

Unfortunately, there is lots of hype involved in weight training. Most of it not backed by research. Actually muscle synthesis decreases during exercise and nearly doubles during recovery between training according to Dr. Carol Meredith of the University of California at Davis. She also stated that additional protein does not increase muscle mass or strength.

Carbohydrates are important sources of energy in weight training since your muscles need fuel (glycogen, which is stored glucose and comes from carbohydrate in the diet). Are you eating about 55-60% of calories from carbohydrates. In a 1500-calorie diet that would be about 206 grams. Take 1500 calories times 55%, then divide by 4 calories per gram. Also what percent of your diet is fat?

PS Avoid raw egg whites as a high protein, low fat food choice as they contain avidin which destroys biotin which is a nutrient.


I've got a question of protein consumption one adult should have normally. Will the overdose of protein be harmful to a normal body function or is it simply not recommended? Since I understand that over-doing those nutritious elements will not bring any benefit to the body as a whole functional unit, about this protein intake I'd like to seek your professional opinion.

Thanks for your attention to this matter.

It depends on what you mean by excess protein. Protein should comprise 10 - 15% of total calories. So if you eat 1,200 calories a day, you only need 30 - 45 grams, but if you are eating 3,000 calories because of your regular activities and exercise program, then you need 75 - 113 grams.

Protein contributes 4 calories per gram. Take your calorie intake and multiply by 10% or 15%, then divide that number by 4 to get the grams of protein you should eat. Protein grams are listed on the new foods labels or you could use nutrition analysis software to track it for you.

Another consideration is what is your age and sex, which determines your RDA for protein. Studies have shown that most healthy persons can stay in positive nitrogen balance (body protein broken down equals body protein being built) on as little as 20 grams of high quality protein per day. Less than that, your body starts breaking down protein structures like internal organs and muscles which reduces your body's ability to function normally and resist disease.

Excess protein, above body needs, is used for fuel or converted to body fat. Any protein excreted is filtered out by the kidneys which usually retains proteins because they are large molecules in the blood. If you have a kidney infection though, protein will show up in your urine. So depending upon how much protein you are eating, you can stress your kidney function.

If you are weight lifting and concerned about increasing muscle mass, then focus on eating a balanced diet with the above amount of protein. If you want to gain weight, then increase calories with a proportionate amount of protein as above.


Does hard boiling an egg destroy some of the amino acids or does it remain the same as raw?

Most of the amino acids (protein) in an egg are found in the white. The yolk is mostly fat. The amino acid content of a raw or cooked egg is basically the same, no matter how you cook it.

Cooking denatures protein. Denature means changing the structure of protein. A cooked egg tastes better than a raw egg and is more appealing.

The nutritional composition of raw and cooked egg is the same. However, the avidin in raw egg whites destroys biotin also found in raw egg whites. Cooking prevents this from happening.

If you hard-boil an egg (whole egg cooked in boiling water), sometimes a green ring will form around the yolk. This happens from boiling eggs too rapidly for too long a time. The hydrogen in the white combines with the sulfur in the yolk to form the green ring. This green ring is harmless, but less attractive looking.




What is the difference between powdered protein supplements such as whey and amino acid pills?

Whey is the clear liquid drained off milk during the making of cheese. It contains protein and all 8 essential amino acids are present, but not in sufficient quantity to be a sole source of protein unless you plan to eat over 2 cups or 133 grams per day. None the less whey (acid or sweet) is a complete protein.

Amino acid pills vary a lot and it depends on the source and structure of the protein. Gelatin and corn contain protein, but are incomplete sources because they don't contain all 8 essential amino acids. Egg whites contain the ideal proportion and content of amino acids. However raw egg whites contain avidin, which destroys another nutrient biotin also in egg white.

Essential amino acids are the building blocks of protein structures (muscles, organs and cells), in man and animals. You should find out what the source of protein is from the label or package insert and whether the pills contain all 8 essential amino acids and in sufficient amounts.

Essential amino acids for adults and their RDA (Recommended Dietary Allowance 1989) are: isoleucine (10 milligrams); leucine (14 milligrams); lysine (12 milligrams); methionine (13 milligrams); phenylalanine (14 milligrams); threonine (7 milligrams); tryptophan (3.5 milligrams); valine (10 milligrams). Infants also need histidine (28 milligrams). These amounts are per kilogram of body weight per day.

Take your body weight and divide by 2.2 to get your weight in kilograms. Next, multiply each amino acid in milligrams by your weight in kilograms. For instance if your weight was 169 pounds divided by 2.2, your weight in kilograms is 77. Next multiply 10 milligrams of isoleucine times 77. Your RDA for isoleucine is 770 milligrams per day. This would include isoleucine from all food sources of protein in a day.

Don't over do consuming protein as food, supplements or pills.


How much protein do I really need per day in grams? I am female, mid-30's. I am currently taking the Fenfluramine, Phentermine combination and eating my usual diet ( low fat, high in complex carbohydrates, veggies, some meat and fish, some dairy).

I saw in the Dunne's Nutrition Almanac, 3rd ed., which a woman within my age range, but weighing less should take in 44 grams of protein per day. There is no way I can take in that much. I've been reading that Americans take in far more protein than we actually need. Is Dunne's figure high? Thanks.

According to the National Academy of Sciences 1989 Recommended Dietary Allowances, you (women 25 to 51+ years of age) need 50 grams of protein per day. Dunne's figure is low and based on the previous 1980 RDA's.

Fenfluramine, Phentermine combination has no effect on increasing or decreasing your protein requirement.

Actually, if you eat six ounces of meat or fish and 2 cups of milk or 2 servings of dairy foods and six servings of complex carbohydrates like bread, cereal, rice or pasta you are probably getting the 50 grams recommended.

Your body uses protein to build and repair tissue. Some cells in your body are replaced rather frequently and need protein in their structure, enzymes or hormones the cell produce.

Americans typically eat very large meat portions, especially they are dining away from home. Some are consuming double their RDA. By the way, adult men 25 to 51+ years of age need 63 grams of protein per day. This is because they are usually bigger and men have a higher percentage of lean muscle tissue to maintain than women.








Search Ask the Dietitian