The myth about protein combining - from the woman who launched the idea

[Korn]

From Complementary Protein Myth Won't Go Away!:

If myths like this not only abound in the general population, but also in the medical community, how can anyone ever learn how to eat healthfully? It is important to correct this misinformation because many people are afraid to follow healthful, plant-based, and/or total vegetarian (vegan) diets because they worry about “incomplete proteins” from plant sources.

How did this “incomplete protein” myth become so widespread?

No small misconception

The “incomplete protein” myth was inadvertently promoted in the 1971 book, Diet for a Small Planet, by Frances Moore Lappe. In it, the author stated that plant foods do not contain all the essential amino acids, so in order to be a healthy vegetarian, you needed to eat a combination of certain plant foods in order to get all of the essential amino acids. It was called the theory of “protein complementing.”

Frances Moore Lappe certainly meant no harm, and her mistake was somewhat understandable. She was not a nutritionist, physiologist, or medical doctor. She was a sociologist trying to end world hunger. She realized that there was a lot of waste in converting vegetable protein into animal protein, and she calculated that if people just ate the plant protein, many more people could be fed. In a later edition of her book (1991), she retracted her statement and basically said that in trying to end one myth—the unsolvable inevitability of world hunger, she created a second one—the myth of the need for “protein complementing.”

In these later editions, she corrects her earlier mistake and clearly states that all plant foods typically consumed as sources of protein contain all the essential amino acids, and that humans are virtually certain of getting enough protein from plant sources if they consume sufficient calories.

From "Complete" Proteins? by Charles R. Attwood, M.D., F.A.A.P.

Proteins are composed of amino acids, 12 of which are manufactured by the human body. Another 9, called essential amino acids, must he obtained from food. Most animal products, such as meat and dairy products, contain all of the essential amino acids and have been designated as containing complete proteins. Most proteins from vegetables also contain all 9 essential amino acids, but 1 or 2 may be low in a particular food compared with a protein from most animal sources. Beans, however, are rich sources of all essential amino acids.

The old ideas about the necessity of carefully combining vegetables at every meal to ensure the supply of essential amino acids has been totally refuted. Modern nutritionists, after observing populations of strict vegetarians who were healthier and lived longer than meat-eaters, now realize that all essential amino acids may be obtained from a variety of vegetables or grains eaten over a one-to-two-day period. This should be a great relief to you as a parent. Even the variety is not as critical as once thought.

A dangerous myth
To wrongly suggest people need to eat animal protein for nutrients will encourage them to add foods that are known to contribute to the incidence of heart disease, diabetes, obesity, and many forms of cancer, to name just a few common problems.

From MYTH: Vegetarians Get Little Protein. Fact: Protein Combining is a Craze

The protein combining idea was contagious -- it appeared in every other book by every other vegetarian author published after that, and made its way into academia, encyclopedia entries, and the American mindset. Unfortunately, the idea that protein combining is necessary was absolutely wrong.

The first problem was that the protein combining theory was just that -- only a theory. There had never been any studies on humans. The idea of protein combining was thus more superstition than science. And it's not surprising that rats would grow differently than humans, since growing rats need ten times as much protein per calorie as growing humans. (Rat milk is 50% protein while human breast milk is only 5%.) Further, if plant foods were really so inferior, then how did cows, pigs, and chickens who eat nothing but grains and other plants get their protein? Wasn't it odd that we were eating farm animals for protein, and they were eating nothing but plants? Finally, plant foods were not even as "deficient" in various amino acids as Lappé had thought.

From Wikipedia:

Protein combining (also protein complementing) is a theory, now largely discredited, that vegetarians, particularly vegans, must eat certain complementary foods like beans and rice together in the same meal, so that plant foods with incomplete essential amino acid content combine to form a complete protein, meeting all amino acid requirements for human growth and maintenance.

The theory was initially promoted in Frances Moore Lappé's 1971 bestseller Diet for a Small Planet. The National Research Council and the American Dietetic Association (ADA) soon picked it up, cautioning vegetarians to be sure to combine their proteins.[1] Later, the ADA reversed itself in its 1988 position paper on vegetarianism. Suzanne Havala, the primary author of the paper, recalls the research process:
There was no basis for [protein combining] that I could see.... I began calling around and talking to people and asking them what the justification was for saying that you had to complement proteins, and there was none. And what I got instead was some interesting insight from people who were knowledgeable and actually felt that there was probably no need to complement proteins. So we went ahead and made that change in the paper. [Note: The paper was approved by peer review and by a delegation vote before becoming official.] And it was a couple of years after that that Vernon Young and Peter Pellet published their paper that became the definitive contemporary guide to protein metabolism in humans. And it also confirmed that complementing proteins at meals was totally unnecessary.[2]

Other nutrition experts and medical professionals who now agree that this theory is outdated include Dennis Gordon[3] and Jeff Novick[4] (registered dietitians), and John A. McDougall[5], Andrew Weil[6], and Charles Attwood[7] (medical doctors).

In fact, the original source of the theory, Frances Moore Lappé, changed her position on protein combining. In the 1981 edition of Diet for a Small Planet, she wrote:
"In 1971 I stressed protein complementarity because I assumed that the only way to get enough protein ... was to create a protein as usable by the body as animal protein. In combating the myth that meat is the only way to get high-quality protein, I reinforced another myth. I gave the impression that in order to get enough protein without meat, considerable care was needed in choosing foods. Actually, it is much easier than I thought.
"With three important exceptions, there is little danger of protein deficiency in a plant food diet. The exceptions are diets very heavily dependent on [1] fruit or on [2] some tubers, such as sweet potatoes or cassava, or on [3] junk food (refined flours, sugars, and fat). Fortunately, relatively few people in the world try to survive on diets in which these foods are virtually the sole source of calories. In all other diets, if people are getting enough calories, they are virtually certain of getting enough protein."[8]

Here's what Marc Lawrence writes about protein combining, in an article called "Complete Protein Myth":

Here’s where it gets interesting. The idea that plant based foods were deficient in certain amino acids was based on studies of the growth of young rats done in the early 1900’s. A subsequent study done in 1952, looked at human requirements for essential amino acids and found them to be very different from rats. Additionally it showed that the requirements for all the essential amino acids in humans could be met by many unprocessed plant foods, without combining, in excess of the recommended levels. The bottom line is that plant protein is “complete.” Vegetables and grains contain all essential amino acids and non-essential amino acids in varying proportions, and will supply in excess of what is necessary for your daily needs.

Whatever all these people write, I still feel better on a diet containing protein rich vegan ingredients (beans, nuts, lentils etc) than on a vegan diet that doesn't. But then again - maybe I'm just hooked on plant proteins.

[Korn]

Some more sites that discuss the myth about vegans having a problem with getting enough protein:


Do We Need To Eat Complementary Proteins All at One Time?

Do We Need To Eat Complementary Proteins All at One Time?

Scientists used to think that vegetarians, and especially vegans, would develop protein deficiency if they didn’t get eight or nine essential amino acids all together in proper amounts at every meal.

Frances Moore Lappé, author of the book ‘Diet For A Small Planet’, is well known for the theory of combining complementary proteins at each meal. In the 20th Anniversary Edition, she has altered her views in light of new knowledge about amino acid storage.

Whenever we eat, our body deposits amino acids into a storage bank, and then withdraws them whenever we need them. So, it’s no longer considered necessary to eat complementary proteins together at one sitting.

Protein Combining:

Each plant food has its own unique amino acid profile, from green leafy veggies to tubers, from barley to quinoa, from lentils to tofu, from macadamias to brazil nuts. By eating a variety of plant foods with 'incomplete proteins' throughout the day, we can easily get enough 'complete protein.' For lacto and ovo-lacto vegetarians, any food can be complemented by the high quality proteins in dairy products or eggs, but it isn't at all necessary to include animal foods to get enough protein in your diet.

In vegan protein combining, there are three broad categories: legumes, grains, nuts & seeds. These can be mixed and matched to get complete protein at any meal, or throughout the day. For instance, the amino acids in legumes (beans & lentils) are balanced by those in grains, nuts and seeds, and vice versa. Vegetables and fruits also contribute significant amounts of protein. A one cup serving of avocado, for example, has 3 grams of complete protein, and a medium potato with skin has 4 g.Vegans can't help getting all the essential amino acids, through eating different combinations of grains, legumes, nuts & seeds, vegetables & fruit several times a day.

Food combining for complete protein isn't a scientific system, where you have to keep track and analyze everything you eat. It's a natural traditional way of eating, which most human beings have eaten and thrived on, for thousands of years. Food is a sensual pleasure, and complete protein is a side benefit.

The chart below shows some examples of food combining for complete protein. While this chart is very limited, in reality the possibilities could fill several pages.

From PCRM's site (Physicians Comitee of Responsible Medicine):

The Building Blocks of Life

Protein is an important nutrient required for the building, maintenance, and repair of tissues in the body. Amino acids, the building blocks of protein, can be synthesized by the body or ingested from food. There are 20 different amino acids in the food we eat, but our body can only make 11 of them. The 9 essential amino acids, which cannot be produced by the body, must be obtained from the diet. A variety of grains, legumes, and vegetables can also provide all of the essential amino acids our bodies require. It was once thought that various plant foods had to be eaten together to get their full protein value, otherwise known as protein combining or protein complementing. We now know that intentional combining is not necessary to obtain all of the essential amino acids.1 As long as the diet contains a variety of grains, legumes, and vegetables, protein needs are easily met.

Protein Requirements

With the traditional Western diet, the average American consumes about double the protein her or his body needs. Additionally, the main sources of protein consumed tend to be animal products, which are also high in fat and saturated fat. Most individuals are surprised to learn that protein needs are actually much less than what they have been consuming. The Recommended Dietary Allowance (RDA) for protein for the average, sedentary adult is only 0.8 grams per kilogram of body weight.2

To find out your average individual need, simply perform the following calculation:
Body weight (in pounds) X 0.36 = recommended protein intake (in grams)

However, even this value has a large margin of safety, and the body’s true need is even lower for most people. Protein needs are increased for women who are pregnant or breastfeeding. In addition, needs are also higher for very active persons. As these groups require additional calories, increased protein needs can easily be met through larger intake of food consumed daily. Extra serving of legumes, tofu, meat substitutes, or other high protein sources can help meet needs that go beyond the current RDA.

The Problems with High-Protein Diets

High-protein diets for weight loss, disease prevention, and enhanced athletic performance have been greatly publicized over recent years. However, these diets are supported by little scientific research. Studies show that the healthiest diet is one that is high in carbohydrate, low in fat, and moderate in protein. Increased intake of whole grains, fruits, and vegetables are recommended for weight control and preventing diseases such as cancer3 and heart disease.4 High-carbohydrate, low-fat, moderate-protein diets are also recommended for optimal athletic performance.5 Contrary to the information on fad diets currently promoted by some popular books, a diet that is high in protein can actually contribute to disease and other health problems.

Osteoporosis. High protein intake is known to encourage urinary calcium losses and has been shown to increase risk of fracture in research studies.6,7 Plant-based diets, which provide adequate protein, can help protect against osteoporosis. Calcium-rich plant foods include leafy green vegetables, beans, and some nuts and seeds as well as fortified fruit juices, cereals, and non-dairy milks.

Cancer. Although fat is the dietary substance most often singled out for increasing one’s risk for cancer, animal protein also plays a role. Specifically, certain proteins present in meat, fish, and poultry, cooked at high temperatures, especially grilling and frying, have been found to produce compounds called heterocyclic amines. These substances have been linked to various cancers including those of the colon and breast.8-10

Long-term high intake of meat, particularly red meat, is associated with significantly increased risk of colorectal cancer. The 1997 report of the World Cancer Research Fund and American Institute for Cancer Research, Food, Nutrition, and the Prevention of Cancer, reported that, based on available evidence, diets high in red meat were considered probable contributors to colorectal cancer risk. In addition, high-protein diets are typically low in dietary fiber. Fiber appears to be protective against cancer.3 A diet rich in whole grains, fruits, and vegetables is important in decreasing cancer risk,3 not to mention adding more healthful sources of protein in the diet.

Impaired Kidney Function. When people eat too much protein, it releases nitrogen into the blood or is digested and metabolized. This places a strain on the kidneys, which must expel the waste through the urine. High-protein diets are associated with reduced kidney function. Over time, individuals who consume very large amounts of protein, particularly animal protein, risk permanent loss of kidney function. Harvard researchers reported recently that high-protein diets were associated with a significant decline in kidney function, based on observations in 1,624 women participating in the Nurses’ Health Study. The good news is that the damage was found only in those who already had reduced kidney function at the study’s outset. The bad news is that as many as one in four adults in the United States may already have reduced kidney function, suggesting that most people who have renal problems are unaware of that fact and do not realize that high-protein diets may put them at risk for further deterioration. The kidney-damaging effect was seen only with animal protein. Plant protein had no harmful effect.11

The American Academy of Family Physicians notes that high animal protein intake is largely responsible for the high prevalence of kidney stones in the United States and other developed countries and recommends protein restriction for the prevention of recurrent kidney stones.12

Heart Disease. Typical high-protein diets are extremely high in dietary cholesterol and saturated fat. The effect of such diets on blood cholesterol levels is a matter of ongoing research. However, such diets pose additional risks to the heart, including increased risk for heart problems immediately following a meal. Evidence indicates that meals high in saturated fat adversely affect the compliance of arteries, increasing the risk of heart attacks.13 Adequate protein can be consumed through a variety of plant products that are cholesterol-free and contain only small amounts of fat.

Weight Loss Sabotage. Many individuals see almost immediate weight loss as a result of following a high-protein diet. In fact, the weight loss is not a result of consuming more protein, but by simply consuming fewer calories. Over the long run, consumption of this type of diet is not practical as it can result in the aforementioned health problems. As with any temporary diet, weight gain is often seen when previous eating habits are resumed. To achieve permanent weight loss while promoting optimal health, the best strategy involves lifestyle changes including a low-fat diet of grains, legumes, fruits, and vegetables combined with regular physical activity.

Protein Checklist

High protein diets are unhealthy. However, adequate but not excess amounts of protein to maintain body tissues, including muscle, are still important and can be easily achieved on a vegetarian diet. If you are uncertain about the adequacy of protein in your diet, take inventory. Although all protein needs are individual, the following guidelines can help you to meet, but not exceed, your needs.

Aim for 5 or more servings of grains each day.This may include 1/2 cup of hot cereal, 1 oz. of dry cereal, or 1 slice of bread. Each serving contains roughly 3 grams of protein.
Aim for 3 or more servings of vegetables each day. This may include 1 cup of raw vegetables, 1/2 cup of cooked vegetables, or 1/2 cup of vegetable juice. Each serving contains about 2 grams of protein.
Aim for 2 to 3 servings of legumes each day. This may include 1/2 cup of cooked beans, 4 oz. of tofu or tempeh, 8 oz. of soymilk, and 1 oz. of nuts. Protein content can vary significantly, particularly with soy and rice milks, so be sure to check labels. Each serving may contain about 4 grams to 10 grams of protein. Meat analogues and substitutes are also great sources of protein that can be added to your daily diet.

International Vegetarian Union:

Should I be worried about getting enough protein on a vegetarian/vegan diet?
No, not as long as you're taking in enough calories. Official recommendations suggest that eating 8% of our daily energy as protein will provide an adequate amount. National and international recommendations for protein intake are based on animal sources of protein such as meat, cow's milk and eggs. Plant proteins may be less digestible because of intrinsic differences in the nature of the protein and the presence of other factors such as fibre, which may reduce protein digestibility by as much as 10%. Nevertheless, dietary studies show the adequacy of plant foods, as sole sources of protein as does the experience of healthy vegans of all ages.

The main protein foods in a vegan diet are the pulses (peas, beans and lentils), nuts, seeds and grains, all of which are relatively energy dense. As the average protein level in pulses is 27% of calories; in nuts and seeds 13%; and in grains 12%, it is easy to see that plant foods can supply the recommended amount of protein as long as the energy requirements are met.

The short answer is: "No, sufficient protein can be obtained by eating a variety of foods", but here is a longer explanation:

Protein is synthesized by the human body out of individual amino acids. The body breaks down food into individual amino acids and then reassembles the proteins it requires.

All amino acids must be present in the body to make proteins. Those that can be synthesized from other amino acids are called "unessential" amino acids. You can live on a diet deficient of these if you eat enough extra of the other amino acids to synthesize these. Those that cannot be synthesized from other amino acids are called "essential" amino acids and must be present in the diet.

Protein that contains all essential amino acids is called "complete" protein. Protein that contains some, but not all essential amino acids is called "incomplete" protein. It used to be believed that all amino acids must be eaten at the same time to form complete proteins. We now know that incomplete proteins can be stored in the body for many days to be combined with other incomplete proteins. As long as all essential amino acids are in the diet, it does not matter if the proteins are complete or incomplete.

The amount of protein recorded on food labels only lists the complete proteins. A product may contain much higher amounts of incomplete protein that is not listed. Combining such products may increase the total amount of protein beyond the levels expected.

The 1989 revision of the FDA's RDA suggests a protein intake of 44-63 grams. Many scientists think this number is too high. Most scientists agree with this number.

Do I need to combine proteins on a vegetarian/vegan diet?
Frances Moore Lappe popularised the idea of protein combining in her book "Diet for a Small Planet" in the '70s, however in her revised edition: "Diet for a Small Planet 10th Anniversary Revised Edition" she has since renounced it.

The 1988 position paper of the American Dietetic Association emphasized that, because amino acids obtained from food can combine with amino acids made in the body it is not necessary to combine protein foods at each meal. Adequate amounts of amino acids will be obtained if a varied vegan diet - containing unrefined grains, legumes, seeds, nuts and vegetables - is eaten on a daily basis.

"Food combining" is another term for the Hay diet and has nothing to do with the concept of protein combining.

What non-meat products can I eat to get protein?

A similar question is answered by the Vegetarian Resource group (USA) at: www.vrg.org/nutshell/faq.htm#protein

Protein in the Vegan Diet

by Reed Mangels, Ph.D., R.D.

Summary

It is very easy for a vegan diet to meet the recommendations for protein, as long as calorie intake is adequate. Strict protein combining is not necessary; it is more important to eat a varied diet throughout the day.
Some Americans are obsessed with protein. Vegans are bombarded with questions about where they get their protein. Athletes used to eat thick steaks before competition because they thought it would improve their performance. Protein supplements are sold at health food stores. This concern about protein is misplaced. Although protein is certainly an essential nutrient which plays many key roles in the way our bodies function, we do not need huge quantities of it. In reality, we need small amounts of protein. Only one calorie out of every ten we take in needs to come from protein 1. Athletes do not need much more protein than the general public 2. Protein supplements are expensive, unnecessary, and even harmful for some people.

How much protein do we need? The RDA recommends that we take in 0.8 grams of protein for every kilogram that we weigh (or about 0.36 grams of protein per pound that we weigh) 1. This recommendation includes a generous safety factor for most people. When we make a few adjustments to account for some plant proteins being digested somewhat differently from animal proteins and for the amino acid mix in some plant proteins, we arrive at a level of 1 gram of protein per kilogram body weight (0.45 grams of protein per pound that we weigh). Since vegans eat a variety of plant protein sources, somewhere between 0.8 and 1 gram of protein per kilogram would be a protein recommendation for vegans. If we do a few calculations we see that the protein recommendation for vegans amounts to close to 10% of calories coming from protein. [For example, a 79 kg vegan male aged 25 to 50 years could have an estimated calorie requirement of 2900 calories per day. His protein needs might be as high as 79 kg x 1 gram/kg = 79 grams of protein. 79 grams of protein x 4 calories/gram of protein = 316 calories from protein per day. 316 calories from protein divided by 2900 calories = 10.1% of calories from protein.] If we look at what vegans are eating, we find that between 10-12% of calories come from protein 3. This contrasts with the protein intake of non-vegetarians, which is close to 14-18% of calories.
So, in the United States it appears that vegan diets are commonly lower in protein than standard American diets. Remember, though, with protein, more (than the RDA) is not necessarily better. There do not appear to be health advantages to consuming a high protein diet. Diets that are high in protein may even increase the risk of osteoporosis 4 and kidney disease 5.

...and:

It is very easy for a vegan diet to meet the recommendations for protein. Nearly all vegetables, beans, grains, nuts, and seeds contain some, and often much, protein. Fruits, sugars, fats, and alcohol do not provide much protein, so a diet based only on these foods would have a good chance of being too low in protein. However, not many vegans we know live on only bananas, hard candy, margarine, and beer. Vegans eating varied diets containing vegetables, beans, grains, nuts, and seeds rarely have any difficulty getting enough protein as long as their diet contains enough energy (calories) to maintain weight. [See the sections on Pregnancy, Lactation, and Infants and Children (pages 176-197 in Simply Vegan, 4th edition) for details about protein needs during these special times.]

[Marrers]

Fruits, sugars, fats, and alcohol do not provide much protein, so a diet based only on these foods would have a good chance of being too low in protein. However, not many vegans we know live on only bananas, hard candy, margarine, and beer.

As one of the few, now trying to mend my ways I found this very interesting. Thanks for collating and posting it Korn.

[bobby]

This information is wonderful!

[dorotkaela]

This is so very helpful! Only today I had a conversation with a friend who was worried about me, because she believed it will be very hard for me to get 'complete' proteins. I just copied loads of information from here and send it to her, lets hope it will put her mind at ease!

[Korn]

Here's an article about the same topic, including a list of what the essential amino acids actually do in the body:

http://www.savvyvegetarian.com/artic...n-veg-diet.php


An excerpt:

The Essential Amino Acids Have Important Functions In The Body:

• Isoleucine (Ile) - for muscle production, maintenance and recovery after workout. Involved in hemoglobin formation, blood sugar levels, blood clot formation and energy.
• Leucine (Leu) - growth hormone production, tissue production and repair, prevents muscle wasting, used in treating conditions such as Parkinson’s disease.
• Lysine (Lys) - calcium absorption, bone development, nitrogen maintenance, tissue repair, hormone production, antibody production.
• Methionine (Met) - fat emulsification, digestion, antioxidant (cancer prevention), arterial plaque prevention (heart health), and heavy metal removal.
• Phenylalanine (Phe) - tyrosine synthesis and the neurochemicals dopamine and norepinephrine. Supports learning and memory, brain processes and mood elevation.
• Threonine (Thr) monitors bodily proteins for maintaining or recycling processes.
• Tryptophan (Trp) - niacin production, serotonin production, pain management, sleep and mood regulation.
• Valine (Val) helps muscle production, recovery, energy, endurance; balances nitrogen levels; used in treatment of alcohol related brain damage.
• Histidine (His) - the 'growth amino' essential for young children. Lack of histidine is associated with impaired speech and growth. Abundant in spirulina, seaweed, sesame, soy, rice and legumes.
• Complete and Incomplete Protein:

ALL plant based foods have varying amounts of protein (plus carbohydrates, fats and other good things), and the body will combine proteins from all sources, to make 'complete protein'. That's true for everybody, veg or non-veg.The term 'complete protein' means that all eight essential amino acids are present in the correct proportion.Foods from animal sources have complete proteins Some foods from the plant kingdom, such as soy and quinoa, have complete protein.The term 'incomplete protein' refers to foods which have all the essential amino acids, but are low in one or more of them. That's called the 'limiting amino acid'.Most plant foods have one or more limiting amino acids which limit the availability of all the other amino acids in the food. That's why these foods are called 'incomplete proteins'.For example, the limiting amino acid in grains is usually lysine (Lys); in legumes it can be methionine (Met) and tryptophan (Trp). So, the low level of Lys in grains is complemented by a higher level in legumes, and vice versa, to make 'complete protein'.However, vegetarians and vegans don't need to worry about complete and incomplete protein. It is NOT NECESSARY for vegetarians and vegans to combine specific protein foods at one sitting to make complete protein.

Complementary Protein Theory Debunked:

Scientists used to think that vegetarians, and especially vegans, would develop protein deficiency if they didn’t get eight or nine essential amino acids all together in proper amounts at every meal.

Frances Moore Lappé, author of ‘Diet For A Small Planet’, is well known for the theory of combining complementary proteins at each meal. In the 20th Anniversary Edition of her book, she has altered her views in light of new knowledge about amino acid storage.Whenever we eat, our body deposits amino acids into a storage bank, and then withdraws them whenever we need them. So, it’s no longer considered necessary to eat complementary proteins together at one sitting, to make complete protein. Your body does that automatically, from all the foods that you eat over the course of a day or so.We still need a healthy variety of good protein building foods, so the body can make enough complete proteins to be happy, even though you don't need to worry about how and when you combine them.

What Vegetarians Should Eat To Get Enough Protein:

Each plant food has its own unique amino acid profile, from green leafy veggies to tubers, from barley to quinoa, from lentils to tofu, from macadamias to brazil nuts. By eating a variety of plant foods with 'incomplete proteins' throughout the day, we can easily get enough 'complete protein.'

[Robinwomb]

I have a new doctor (my last one I had for seven years left the practice to pursue other administrative duties) and while at least this new one accepts my being vegan, she constantly preaches the complementary protein myth. I have tried to explain that this has been proven wrong but she is strongly insistent on it. Maybe I will show her these articles and if she still persists I guess it's time to go shopping for another doctor again. Sighs.

[Cacique]

Sorry that you have to deal with that, Robinwomb.

I can think of a few responses; "Yeah, thanks. I'm well aware of that myth and am not interested. Any chance you could drop it or should I walk out now?" or maybe "Well, that's nice, but I'd rather take the word of many professionals than a single one." Maybe also "Thanks, but lets remember that you're a general practitioner, not an expert in nutrition."

I would, of course, give them the info first and see if they shut up about the protein myth. Maybe you could find some type of chart that shows the amount of protein on things like legumes, tofu, tempeh, etc.

Good luck!

[Korn]

she constantly preaches the complementary protein myth.

It would probably be a good idea to ask her to give you the name of, or ideally: a link to - a scientific report which documents that she is right.

[Robinwomb]

Thanks guys! I will definitely be armed and prepared with information and a few good responses next time. I just feel like if I ignore her comments and let it go she will not respect me and will think I am being irresponsible and not eating heatlhy and taking care of myself. Unlike my former doctor, this doctor does not fully understand and has not seen first hand how sick I once was (eating disorder as well as all kinds of problems stemming from an unnecessary surgery I had) and how very hard I have worked over the years to overcome it, learn to forgive and love myself again, and just to be healthy. Never mind my commitment to living out my vegan values. I guess I just need to be patient and give it time.

[JD Mumma]

Korn,

Thanks for all the great links and information. It seem the main issue is length of time amino-acids are available after digestion

Q: Do you have any information specifically referencing length of time amino-acids are available after digestion?

I am in a debate and the other person is saying that all protein combining needs to happen in 24 hours. My recollection is that over a decade ago I had learned that they found out that the rats had a 4 hour pool of amino acids available and that when they finally tested humans they found out that they had a 4 DAY pool, but I have not yet been able to corroborate that statement.
Thanks!

[Robinwomb]

I am taking Anatomy & Physiology in college right now (finally almost done with this two semester course yeah!) and while we did not study the chapter on Nutrition and Metabolism, I glanced through it myself and was discouraged to find this:

"The all-or-none rule: All amino acids needed to make a particular protein must be present in a cell at the same time and in sufficient amounts. If one is missing, the protein cannot be made. Because essential amino acids cannot be stored, those not used immediately to build proteins are oxidized for energy or converted to carbohydrates or fats. "

"Animal products contain the highest quality proteins, in other words, those with the greatest amount and best ratios of essential amino acids. Proteins in eggs, milk, fish, and most meats are complete proteins that meet all the body's amino acid requirements for tissue maintenance and growth. Legumes, nuts and cereals are protein rich, but their proteins are nutritionally incomplete because they are low in one or more of the essential amino acids. The exception to this genaralization is soybeans, plant-derived complete proteins. Strict vegetarians must carefully plan their diets to obtain all of the essential amino acids and prevent protein malnutrition. When ingested together, cereal grains and legumes provide all the essential amino acids. Some combination of these foods is found in the diets of all cultures. For nonvegetarians, grains and legumes are useful as partial substitutes for more expensive animal products."

"In negative nitrogen balance, protein breakdown for energy exceeds the amount of protein being incorporated into tissues. This occurs during physical and emotional stress or when the quality of dietary protein is poor or during starvation."

To give the authors credit, they do add this:

"Most Americans eat far more protein than they need. Prolonged high protein consumption may lead to bone loss. This may occur because metabolizing sulfur containing amino acidds makes the blood more acidic and calcium is pulled from the bones to buffer these acids".

Human Anatomy & Physiology 9th edition
Elaine N. Marieb, R.N., Ph.D and Katja Hoehn, M.D., Ph.D
c 2007, 2010, 2013

If I had more time (finals week is next week eek) I would do some research myself into how long amino acids take to be digested. My school book goes into great detail about the process of breakdown, digestion and absorption of proteins, but not specifically how long it takes, other than to say that about 125 grams of protein are digested per day (not all dietary as some proteins in the body come from mucosa tissue and other sources).

Sometimes I just don't know what to believe, but surely the protein combining theory is debunk as there are many long term vegans out there that have done fine without making an effort to do this, Donal Watson was one for instance who lived a long time as a vegan and was quite healthy and active. I get irritated with textbooks as they are not all facts either and can have some cultural and personal bias just like anything else written.

[JD Mumma]

Thanks for the quotes Robinwomb!

I keep reading people (scientist, medical doctors, registered dietitians...) that there is no storage of protein, yet they fail to mention the labile protein reserve.

"The concept of a labile protein reserve is based on the relatively slow establishment of a new equilibrium in the rate of nitrogen excretion after an abrupt change in dietary supply. The evidence reviewed shows that a majority of this nitrogen is derived from or deposited in skeletal muscle proteins." Labile protein reserves and protein turnover
http://www.ncbi.nlm.nih.gov/pubmed/325030

"...which can be gained or lost from the body as a short-term store for use in emergencies or to take account of day-to-day variations in dietary intake. Studies in animals have suggested that this immediate labile protein store is contained in the liver and visceral tissues, as their protein content decreases very rapidly during starvation or protein depletion (by as much as 40 percent), while skeletal muscle protein drops much more slowly (Swick and Benevenga, 1977). During this situation, protein break- down becomes a source of indispensable amino acid needs for synthesis of proteins critical to maintaining essential body function (Reeds et al., 1994). This labile protein reserve in humans is unlikely to account for more than about 1 percent of total body protein (Waterlow, 1969; Young et al., 1968); the labile protein reserve is similar in weight to the glycogen store.
http://www.nap.edu/openbook.php?reco...10490&page=589



"The concept of a labile protein reserve is based on the relatively slow establishment of a new equilibrium in the rate of nitrogen excretion after an abrupt change in dietary supply. The evidence reviewed shows that a majority of this nitrogen is derived from or deposited in skeletal muscle proteins." Labile protein reserves and protein turnover
http://www.ncbi.nlm.nih.gov/pubmed/325030