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The protein conundrum

 

In this new series on different aspects of using food to Health Yourself, Victor Katch examines the conundrum of proteins; their different kinds, where they come from, how much you need, and the problem of eating meat as your major source of protein. As an alternative, he suggests a whole-food, plant-based approach to fulfilling protein needs.

In last month’s column on confined animal feeding operations (CAFOs) I brought up the many problems related to decreasing meat quality resulting from industrial farming. Many of the emails I received raised questions regarding the role of meat in our diet, specifically related to protein quality. How could someone get enough protein, regardless of where and how it was grown, if one did not eat meat?

In this month’s column I discuss the many aspects of protein and try to clear up some common misconceptions. In subsequent columns I will discuss fat and carbohydrate nutrients and address the roles these nutrients play in your personal health promotion.

Macro- and Micronutrients

There are five major nutrients. Macronutrients consist of carbohydrates (sugars), lipids (from the Greek lipos, meaning “fat), and proteins (from Greek, meaning “of prime importance”). Macronutrients provide energy to maintain bodily functions during rest and physical activity. They serve to preserve the body’s structural and functional integrity.

Micronutrients consist of vitamins and minerals, found in the watery medium of the body, that play highly specific roles in facilitating energy transfer and tissue synthesis. Micronutrients contain no energy.

About proteins

Combinations of linked amino acids form proteins. An average-sized adult contains between 22-26 pounds of protein, with skeletal muscle containing the largest quantity (13-18 pounds; 60- 75 percent of all the body’s protein). Additionally, approximately 7.4 oz. (210 grams) of amino acids exist in free form, largely as glutamine, a key amino acid that serves as fuel for immune system cells.

The typical adult generally ingests about 10-15 percent of their total calories as protein. During digestion, protein breaks down to amino acids for absorption by the small intestine. Amino acids not used to synthesize protein or other compounds (e.g., hormones), or not used for energy metabolism quickly convert to fat, and store in different fat pads around the body (think belly fat,  thigh fat, and … ). That’s right, excess proteins convert to fat for storage!

Structurally, proteins resemble carbohydrates and fats because they contain carbon, oxygen, and hydrogen atoms. But they also contain about 16 percent nitrogen, along with sulfur and occasionally phosphorus, cobalt, and iron. A combination of more than 50 linked amino acids forms a protein. Approximately 50,000 different protein-containing compounds exist in the body. The biochemical functions and properties of each protein depend on the sequence of specific amino acids.

There are 20 different amino acids required by the body. The potential for combining these 20 amino acids produces an almost infinite number of possible proteins, depending on their amino acid combinations. For example, linking just three different amino acids could generate 203, or 8,000, different proteins!

Kinds of protein

The body cannot synthesize eight amino acids (nine in children and some older adults), so they must be consumed in foods that contain them. We call these essential (or indispensable) amino acids. You may have heard or read about these essential amino acids: isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine.

With a few exceptions, the body manufactures the remaining nine nonessential amino acids. The term nonessential does not indicate a lack of importance; rather, they are synthesized from other compounds already in the body at a rate that meets the body’s needs for normal growth and tissue repair.

Animals and plants both manufacture proteins that contain essential amino acids.

Plants synthesize amino acids by incorporating nitrogen from the soil (along with carbon, oxygen, and hydrogen from air and water). In contrast, animals have no broad capability for amino acid synthesis. Instead, they consume most of their protein by eating plants (or other animals).

Complete proteins (sometimes referred to as higher-quality proteins) come from foods that contain all the essential amino acids in the quantity and correct ratio the body needs. An incomplete protein lacks one or more essential amino acid. A diet of incomplete protein can eventually lead to protein malnutrition, whether or not the food sources consumed contain an adequate amount of energy or protein.

How much protein do you need?

It is impossible to recommend precisely the exact amount of protein any one individual needs. It can depend on many factors including body size, level of physical activity, gender, etc. Through the years, however, beginning in 1943 and updated periodically, the Food and Nutrition Board of the National Research Council/National Academy of Science has generated nutritional guidelines based on “best” scientific evidence. Currently, the Recommended Dietary Allowance (RDA) for protein, expressed as a daily average, represents a liberal yet safe excess to prevent protein deficiencies in practically all healthy persons. The RDA represents a probability statement for adequate nutrition; as nutrient intake falls below the RDA, the statistical probability for “malnourishment” increases for that person and the probability progressively increases with lower intake.

The following table lists the protein RDAs for adolescents and adults. On average, 0.029 oz. of protein per 2.2 lbs body weight (0.8 g per kg) represents the RDA.

Protein Recommended Dietary Allowance (RDA) for Adolescent and Adult Mean and Women
Recommended Amount

Men

Women

Adolescent

Adult

Adolescent

Adult

Grams protein perk kg body weight

0.9

0.8

0.9

0.8

Grams protein based on average body weight

59

56

50

44

 To put this in perspective by way of an example, I weigh 156 lbs (70.7 kg), so my protein requirement is 4.5 oz. (57 g) protein per day (0.8 g/kg x 70.7 kg).

Think about this for a moment. To get my protein requirement I could visit my local McDonald’s and consume  one quarter pounder with bacon and  cheese (37 g; 600 kcal);  one large order of french fries (6 g; 500 kcal); and  one (16 fl. oz.) chocolate McCafe shake (15 g; 700 kcal). At this single meal with only three items I’ve already consumed my RDA for protein and a whopping 1800 kcal, and I haven’t even counted my breakfast or what I would eat for dinner. At this rate, I could overdose on protein, increase my percent of body fat (remember, excess protein stores as fat), and consume way too many calories. WOW!

The protein RDA holds even for overweight persons; it includes a reserve of about 25 percent to account for individual differences in the protein requirement for about 97 percent of the population. Generally, the protein RDA (and the quantity of the required essential amino acids) decreases with age. Pregnant women should increase total daily protein intake by a little under 1 oz. per day, and nursing mothers should increase their intake by 0.35 oz. per day. Stress, disease, and injury usually increase daily protein requirements.

Protein sources

In my Nutrition, Exercise, and Weight Control class, I poll students every semester about why they eat meat. Believe me, I get some strange answers, but more than 98 percent of them say (incorrectly) you need to eat meat everyday to ensure adequate protein intake.

Sources of food that contain high-quality protein (rated on a scale from 0-100) are shown in the table below. Eggs provide the optimal mixture of essential amino acids among all foods; hence they earn a protein rating of 100.

Examples of common sources of dietary protein rated for protein quality.
Food Protein Rating
Eggs
Quinoa (raw)
Fish
Lean beef
Cow’s milk
Brown rice
White rice
Soybeans
Brewer’s hash
Whole-grain wheat
Peanuts
Dry beans
White potato
100
86
70
69
60
57
56
57
45
44
43
34
34

With the exception of a few plant proteins like soy-isolate proteins (such as tofu and quinoa, which also provide all essential amino acids), most of the high-quality proteins in our diet come from animal sources. However, a major problem with relying on animal sources for the majority of dietary protein, as is the case in most major industrialized nations, is the relatively high cholesterol and saturated fatty acid intake that comes with them (more on this below).

While plant-based foods remain incomplete in one or more essential amino acids, eating a variety of grains, fruits, and other plant-based foods (vegetables) can easily supply all of the essential amino acids. 

The problem of eating meat as your major source for protein

Undeniably, meat is a fine source of high-quality protein, but relying on meat as a major source of protein leads to unintended health consequences that are now coming to light.

The scientific research literature is growing (although admittedly inconsistent) showing a strong causal link between animal consumption (primarily red meat) and an increasing number of health-related problems. These studies stand up to strong scientific scrutiny and their increasing frequency in scientific journals cannot be dismissed as frivolous.

For example, red meat associates with development of type 2 diabetes and cardiovascular disease; increased weight and body fat; obesity-related inflammation and insulin resistance; a higher plasma concentration of C-reactive protein (a cardiovascular inflammatory biomarker); abnormal glucose metabolism; increased risk of stroke; high blood pressure; kidney disease; and decreased longevity.

The scientific weight of accumulated research suggests substituting servings of animal-based protein (in particular, red meat) with plant-based protein to improve health outcomes. Thus, meat eaters should consider at the minimum:

  • reducing the amount of animal products consumed per day
  • eliminate meat at least one day per week
  • make meat a side dish rather than a main dish
  • adopt a whole food, plant-based diet!

A whole-food, plant-based diet: The vegan approach

True vegetarians, or vegans, consume nutrients from only two sources—the plant kingdom and dietary supplements (although not necessary). Vegans constitute less than 4 percent of the U.S. population, yet between 5-7 percent of Americans consider themselves “almost” vegetarians. For vegans, nutritional diversity remains the key to obtain all of the essential amino acids. For example, a vegan diet contains all the essential amino acids if the recommended intake for protein contains 60 percent of protein from grain products, 35 percent from legumes, and 5 percent from green leafy vegetables.

An increasing number of competitive and champion athletes consume diets consisting predominantly of nutrients from varied plant sources, including some dairy and meat products with no degradation in performance. In contrast to diets that rely heavily on animal sources for protein, well-balanced vegan and vegetarian-type diets provide abundant good carbs so crucial for good health and not surprisingly intense, prolonged training. Such diets contain abundant fiber and little or no cholesterol. A plant-based diet also includes more than enough diverse phytochemicals and antioxidant vitamins.

A lactovegetarian diet provides milk and related products such as ice cream, cheese, and yogurt. The lactovegetarian approach minimizes the difficulty of consuming sufficient high-quality protein and increases the intake of calcium, phosphorus, and vitamin B12 (produced by bacteria in the digestive tract of animals). Adding an egg to the diet (ovolactovegetarian) ensures sufficient high-quality protein intake.

One of the most common myths about the vegan diet is that after ditching meat it becomes nearly impossible to get enough protein. The table below offers some examples of plant-based options to get your protein.

 

Food Amount Grams Protein
Avocado 1 5-6
Spinach 1 cup 5
Cooked kale 2 cups 5
Boiled peas 1 cup 9
Broccoli 1 cup 5
Sweet potato 1 cup cooked 5
Soybeans 1 cup 28
Tofu 1 cup 22
Tempeh 1 cup 30
Lentils 1 cup 18
Refried beans 1 cup 15.5
Garbanzo beans (and hummus) 1 cup 14.5
Pinto, kidney, black beans 1 cup 13-15
Peanuts 1 oz. 6.5
Cashews 1 oz. 4,4
Sesame seeds 1 oz. 6.5
Tahini 3 tbsp. 8
Walnuts 1/4 cup (2 oz.) 5
Pistachios 1 oz. 5.8
Almonds 2 tbsp. 4
Nut butters (peanut, almond, cashew) 2 tbsp. 8
Non-dairy milk (soy, almond, ancient grain) 1 cup 7-9
Grains: Quinoa (amaranth, bulgar, wheat germ, oat bran) 1 cup 9
Seitan or flavored wheat gluten 1 cup 52
Oatmeal 1 cup 6
Sprouted grain products (buns, tortillas) 1 slice 7-10

 

References:

  • 1Anthelme Brillat-Savarin, Physiologie du Gout, ou Meditations de Gastronomie Transcendante, 1826.
  • Azadbakht, L., Esmaillzadeh A., Red meat intake is associated with metabolic syndrome and the plasma C-reactive protein concentration in women. Journal of Nutrition 2009;139:335–9.
  • Feskens, E.J. et al. Meat consumption, diabetes, and its complications. Curr Diab Rep 2013;13:298–306.
  • Montonen, J. et al. Consumption of red meat and whole-grain bread in relation to biomarkers of obesity, inflammation, glucose metabolism and oxidative stress. Eur J Nutr 2013;52:337–45.
  • Mursu, J. et al. Intake of fruit, berries and vegetables and risk of type 2 diabetes in Finnish men: the Kuopio Ischaemic Heart Disease Risk Factor Study. Am J Clin Nutr 2014;99:328–33.
  • Pan, A. et al. Red meat consumption and risk of type 2 diabetes: 3 cohorts of US adults and an updated meta-analysis. American Journal of Clinical Nutrition 2011;94:1088–96.
  • Sylvia, H.L. et al. Association between red meat intake and biomarkers of inflammation and glucose metabolism in women. American Journal of Clinical Nutrition 2014;99:352-60.
  • The InterAct Consortium. Association between dietary meat consumption and incident type 2 diabetes: the EPIC-InterAct study. Diabetologia 2013;56:47–59.
  • Vergnaud, A-C et al. Meat consumption and prospective weight change in participants of the EPIC-PANACEA study. Am J Clin Nutr 2010;92:398–407.

Comments

  1. John MacKenzie - 1950

    Another gem. Thanks. J.

    Reply

    • Shelby Johnson - 1983

      Excellent article, if you are interested in reading more about the essential nutrients for maintaining a healthy body, read the research by Dr. Joel Wallach, founder of Youngeity. For his products visit me at www. Shelbyjohnson.my90forlife.com

      Reply

  2. William Morgan - 1994

    1) the studies damning red meat, how do they control or do they for other factors that can explain same phenomenon i.e. CAFO meat vs grass fed, high omega 6 fat consumption and refined carb consumption
    2) why no mention of the deleterious effects of soy on human especially male health
    3) Why no mention of the massive amounts of carbs that do indeed go right to belly fat required to get enough protein from grains and legumes even quinoa
    4)why no mention of the inflamatory effects of grain consumption?
    comment; for 99% of human and pre human primate existence protein in form of meat, eggs, insects, shellfish sustained us. The plant based approach only became possible in past several thousand years, even in India it is supplemented with dairy. I am not buying the viability of plant based diet, way way too many carbs and inflamatory compounds from grain, humans are omnivores.

    Reply

    • Elizabeth Zide, M.D. - 1992

      These are exactly the types of questions that need to be asked about the studies that are referred to in this article! It is well known that carbohydrates, particularly grains, are a significant contributor to inflammation in the body. It is also amazing to me that we can ignore how the rate of obesity increased in this country after we were encouraged to change our diet to a carbohydrate based, low fat diet in the 80’s. We only need to look at cultures that have traditionally subsisted on an almost entirely animal protein diet to see the fallacy of the idea that red meat is the main dietary culprit of health issues in this country!

      Reply

    • Janet Webber - 1973

      Aloha William, I agree with you on the grains and soy, but I have to disagree with you on the time frame of introduction of plant based diet. The introduction of plants, i.e. grains, around 10,000+ years ago was of the agricultural variety, but BEFORE that we were totally ‘hunter-gatherers’ with an emphasis on the gathering a wide variety of plants, leaves, roots, insects, etc. Only a small percentage of their intake was intermittent red meat animal scores and that did increase in time with more and better weapons and tools. You might be interested in book, THE STORY OF THE HUMAN BODY by Daniel E Lieberman. I am really enjoying this tremendously.

      Reply

    • Victor Katch

      Mr Morgan, Thanks for your comments and interest in my article. The purpose of this article was to discuss proteins and different ways to obtain adequate amounts in one’s diet. Most research suggests that the majority of people in the U.S. believe that the only way to get sufficient protein is via animal-based foods. This has led to over-consumption of meat (and protein) in our culture. I was only trying to point out that other options are available. In future columns I will discuss various aspects of fat and carbohydrate and what individuals need to consider when making informed food choices. I welcome your comments and input.

      Reply

  3. Robyn Tonkin - 1982

    Why is an article this important being written by someone with no health sciences background? Since type II diabetes is a disorder of carbohydrate metabolism, how can it be “associated” with eating red meat? By using studies not carefully controlled for carbohydrate ingestion, that’s how. The admonition to combine plant proteins to obtain complete protein is a tired old theory pushed by Frances Moore Lappe’ in the 1970’s–she called it “protein complementarity”. I ask you–what did we eat during the long north European winters in prehistory? We ate meat almost exclusively. Over hundreds of thousands of generations, would our specie evolve in opposition to its main food source? We have only been eating beans, grains, and starchy fruits since civilization and agriculture emerged– a few thousand years ago. It does not logically follow that liking the concept of living on plant proteins and carbohydrates means it is the biologically correct thing to do.

    Reply

    • Robert Martens - 1971

      Agree with Robyn. I am wondering if Mr. Katch is familiar with the peer reviewed research exposing the dangerous fallout from carbs that Dr. Wm. Davis reveals in his books. (e.g. “Wheat Belly”). Or, the benefits to the brain of cholesterol (no, it is not the villain we have been taught) clearly stated by Dr. David Perlmutter in “Grain Brain”.

      Reply

    • Zachary Jablonski - 2014

      While I have seen several excellent arguments towards the adoption of a vegan diet, the “argument” being made here is filled with bizarre comparisons, inadequate counter-examples, and a few misconceptions.
      First, and this is being a bit nitpicky, micro-nutrients can be water soluble, but there are also many important fat-soluble micro-nutrients such as vitamins A, D, and K.
      Your information about amino acids and daily requirements generally spot on, as far as I can tell. Two points here though:
      One, I don’t understand why you would stoop to using a straw man in your argument here: nobody who is attempting to meet protein requirements would argue that McDonalds is even remotely a source of choice. Of course you meet calorie requirements getting your daily protein with that route – you aren’t listing the gratuitous amounts of carbs/fats included in that meal! I am disappointed in you as an author for choosing the easy route here.
      Two, you said excess amino-acids are converted to fat – that is dead wrong. First off, the majority of amino-acids are glucogenic, meaning they can be converted to glucose in the liver as needed by the body. While a few amino acids are ketogenic, they produce ketone bodies and NOT fatty acids. These ketone bodies can be used to make fatty acids, that is true, but it requires an investment of energy from the body. This highly unlikely lipogenesis would only occur if you consumed so much protein that you exceeded your daily calorie requirements. I challenge you to provide sources to the contrary; in return, I would be happy to provide the textbooks I consulted before I wrote this.
      Let’s move on to the protein sources section. You mention “protein quality”, which I assume is a measure of completeness since you left it undefined. Your list is cherry-picked towards vegan alternatives, pardon the pun – why didn’t you include other meat sources of protein such as fish (like tuna), turkey and chicken, which have more amino acids and less fat than beef? A calorie/gram of protein ratio chart may have proved your point better, as well.
      Robyn has already voiced my own thoughts of your mentioning the supposed correlation of red meat with diabetes. But I would like to note that you were originally arguing for plant sources over all types of meat – by focusing solely on the deficiencies of red meat and ignoring better alternatives, are you really proving your point?
      I agree with you that meat consumption is not the only way, or even the best way, to get adequate daily protein. There is definitely a general misconception that you can’t get enough protein on a vegan diet, and that simply isn’t true. But if you’re going to write an article that attempts to educate readers, please drop the ridiculous counter-examples and spend the time to research your points.

      Reply

    • Janet Webber - 1973

      Aloha Robyn,
      I am really interested in what you are saying, especially the stuff about diabetes. I think you would really like Daniel E Lieberman’s book, THE STORY OF THE HUMAN BODY. He goes into how the body adapted and evolved from the very beginning with a focused look at ‘mismatched’ diseases, which diabetes is, according to his work in evolutionary biology. Enjoy !!

      Reply

    • Victor Katch

      Thank you for your interest in my article and your timely comments.
      I would like to briefly respond regarding your comment that I have no “health-science” background and hence am not qualified to write about nutrition or health with any authority.
      For your consideration, I have both an undergraduate (B.S.) and graduate (M.S. and Ed.D) degree in Kinesiology (used to be called Physical Education). My graduate degree is from the University of California, Berkeley. Kinesiology is the study of movement that includes different areas like exercise physiology, biomechanics and motor behavior, among others. My area of study, and my research over the last 42 years here at UM is in the field of exercise physiology.
      My particular research interests have centered on exercise, nutrition, weight control and human performance. I have published more than 100 articles in peer reviewed journals, and co-authored 3 major textbooks in the area. My text, “Exercise Physiology: Nutrition, Energy, and Human Performance” (Lippincott Williams & Wilkins) is now in its eighth edition and is considered by many to be the leading book in the field; it has been a winner of the prestigious British Medical Association top book award in the medical/physiology area. One of my other textbook, “Sports & Exercise Nutrition” (Lippincott Williams & Wilkins) is also a leading book in the emerging field of exercise nutrition.
      Also, I was founder and director of the UM Weight Control Clinic that worked with clients on integrating research-based information about energy intake and output to regulate weight. We regularly designed integrated diets, exercise programs, and counseling to help individuals lose, maintain, and gain the right kind of body weight. I am very proud of this outreach program where we were able to teach individuals about the role of proper nutrition in maintaining personal health.
      Finally, over the last 15 years or so I have been teaching a course titled “Exercise, Nutrition, and Weight Control” that is open to all students at UM. I originated this course and it regularly enrolls 175-225 students per term and is a recommended course for nursing, pharmacology, and premed students. It is one of only a few undergraduate UM courses dealing with nutrition and physical activity. This courses’ curriculum includes many of the topic areas that are required for students entering graduate nutrition and dietetics programs.
      So, I encourage you to continue to comment about, or to point to inaccuracies in my articles, but please don’t suggest I don’t have a sufficient academic background in the areas of health, nutrition and physical activity.

      Reply

  4. seema patel - 1988 and 2001

    excellent information. Being plant based is critical for decreasing long term chronic problems and in the prevention of chronic disease. We need to do a better job in labeling food especially vegetables and fruit because people just don’t understand.

    Reply

  5. Joanna Connelly - 2013

    As an almost vegan this was a good read, but from the numbers provided here it looks like I’m only getting about 3/4 of my needed protein daily, even with a whole foods, plant based diet (rather than a vegan diet supplemented with less healthy items like Oreos). I guess I need to step up my game a bit.

    Reply

  6. Gary Pace - 1964, 1970

    While I generally approve of the premise of the article, I must agree with Zachary Jablonski – 2014 about the nature of the argument.
    To add to the nitpicking, I cannot find tiyisoleucine in any of my old biochemistry books and must assume it is a typographical error; maybe an editorial problem.
    I am certainly not a mathematician, but I have a few questions I cannot resolve. You seem to use the number 20 to the power of three because “There are 20 different amino acids required by the body.” However, you used the statement that …”50 linked amino acids forms a protein.” If you want to know the number of different types of proteins 50 units in length using three different units, wouldn’t you use the number 50 x 50 x 50 = 125,000 possibilities? If I am correct, it would make your case for the potential diversity of proteins even greater. The actual number would be more like 50 raised to the power of 20 although even these numbers are too low to account for the total protein diversity in the entire biological world.
    Finally, I may be missing something, but since there are 28.4 g/oz, 57 g would only allow you 2.01 oz of protein per day. I have been unable to figure out how you calculated the …”4.5 oz (57g)”…

    Reply

    • Victor Katch

      Mr. Pace. Thanks for your comments and for pointing out some errors in my article.
      1) You are correct: tiyisoleucine was a typo not caught in editing; it should read Isoleucine
      2) The calculation of the number of proteins is 20 x 20 x 20 = 8000. Some proteins have more than 50 linked amino acids; I was not trying to illustrate amino acid numbers, but protein numbers. Sorry for the confusion.
      3) Your are correct here too: 57 g = 2.01 oz
      Thanks
      Vic Katch

      Reply

  7. Fred Ingersoll

    Perhaps the good professor can explain to us why the consumption of beef has been steadily declining since the 60’s and is in fact at the lowest level in fifty years, yet obesity has been steadily increasing at the same time in an almost perfect inverse correlation?
    The professor with an agenda also happened to miss this news summary:
    Study: Saturated Fat May Not Increase Risk Of Heart Attack, Other Cardiac Events.
    The New York Times (3/18, O’Connor) “Well” blog reports that research published in the Annals of Internal Medicine “found no evidence that eating saturated fat increased heart attacks and other cardiac events.” These “findings are part of a growing body of research that has challenged the accepted wisdom that saturated fat is inherently bad for you and will continue the debate about what foods are best to eat.”
    Bloomberg News (3/18, Ostrow) reports that the data also indicated that “food rich in fish oils such as omega-3 don’t reduce heart-disease risk.”
    The CNN (3/17) “The Chart” blog reports that the investigators came to these conclusions after reviewing “a large spectrum of studies on the subject: 32 observational studies looking at fatty acids from dietary intake, 17 observational studies of fatty acid biomarkers, and 27 randomized, controlled trials examining fatty acid supplementation.”
    Forbes (3/17) contributor Larry Husten writes that a “second study, published in JAMA Internal Medicine (3/18), reports the cardiovascular outcomes of patients who participated in AREDS2 (Age-Related Eye Disease Study 2).” Just over 4,200 “patients with age-related macular degeneration were randomized twice, to either omega-3 fatty acids (DHA 350 mg and EPA 650 mg) or placebo and also to lutein and zeaxanthin (carotenoids found in the eye) or placebo.” Investigators found that “after 4.8 years of followup there was no significant reduction in cardiovascular outcomes in either of the treatment groups.”

    Reply

  8. Cindy Schumacher - 1996

    I am caught between one daughter the vegetarian and one daughter the carnivore–both espousing the benefits of their particular diet. I finally just recently decided to eat fish, vegetables, fruits and some grains, since none of the “experts” can agree.

    Reply

  9. Matt Brest - 1987

    I always enjoy your insight, and I now have a much better understanding of the role of proteins, as well as a greater understanding of complete proteins. Very well written and I look forward to your future articles.

    Reply

  10. Stanley Beekman - 1968

    Vegans do not have any B12 in their diet. The question was how did the Indian civilization survive without B12. A study was done and they found that they do not wash their fruits and vegetables. The insect poop on it is chock full of B12.
    In this country we wash our fruits and vegetables, so long term the Vegans will not survive. Signs of B12 deficiency include Megaloblastic anemia (which may be hidden due to Folic Acid), peripheral neuropathy affecting the posterior columns (2 point touch, proprioception [which will affect balance], and vibration), black finger nails, premature greying, and loss of energy.

    Reply

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