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    Archive for the ‘amino acids’ Category

    You Ask, I Answer: L-Carnitine

    reflex_l_carnitine_120capsI have a dental practice, and one of my patients is a competitive bodybuilder.

    The other day he and I were talking about weight loss and he told me to buy L-Carnitine.  He said that if I took some an hour before working out, I would lose more fat more quickly.

    Have you heard this before?

    — Laura (last name withheld)
    Annapolis, MD

    I have heard indeed heard this myth before.  More times than I’d like to admit, to be frank.

    L-Carnitine is an amino acid  involved in fat metabolism (meaning it helps break down fats so they can later be used for energy by the body).

    It is not essential (we do not need to get it from food) since we  make carnitine from other amino acids in our diets that are essential.

    Manufacturers of ergogenic aids are quick to point out that L-carnitine helps speed up fat loss while providing more energy and helping increase lean muscle mass.  In other words, it’s yet another “miracle pill.”

    Alas, studies relating to sports nutrition have found no benefit from L-carnitine supplementation. 

    What many people forget is that they already consume a fair share of this amino acid from food if they eat  meat and dairy products.

    Remember, since carnitine is not essential, you do not need to get it from the diet.  A diet that does not include meat and dairy does not make one “carnitine deficient.”

    As with many other supplements, I say:  keep your money safe in your wallet.


    You Ask, I Answer: Amino Acids in Plant Protein

    FEA LV DietbooksI was reading a copy of Sugar Busters (it was at my aunt’s house, I promise I didn’t buy it, Andy!) and at one point the authors mention that two essential amino acids (methionine and lysine) are best absorbed by the body if they are consumed from animal sources.

    I thought vegetarian diets were fine from a protein and amino acid standpoint?

    — Dawn (last name withheld)
    Jacksonville, FL

    Ah, yes, Sugar Busters — one of the iconic books of the latest low-carb revolution.

    Interestingly, none of the four authors (three of whom are doctors) have backgrounds — or, actually, a single degree — in nutrition.

    It always confuses me why people think an “MD” credential automatically means someone is well-versed in nutrition.

    A cardiac surgeon with top honors can work wonders in the operating room and be up on the latest technologies, but most of them have next to little nutrition knowledge.  Let’s leave something as specialized and complex as heart surgery to them and nutrition to those who have spent years studying it.

    Anyhow, onto your question.

    There are nine essential amino acids.  In nutrition, the term ‘essential’ means that we absolutely must get that nutrient or component from our diets.

    Animal products are called ‘complete proteins’ because they contain all nine essential amino acids.

    Most plant-based sources of protein (vegetables, whole grains, beans, nuts, etc.) are ‘incomplete proteins’ because they offer some, but not all of the essential amino acids.  There are some exceptions, though — hemp seeds, chia seeds, and soy.

    This “complete versus incomplete protein” issue is a moot point, though.

    It just so happens that the essential amino acids lacking in whole grains, for example, are abundant in legumes (and vice versa).  Hence, a diet entirely composed of plant protein is just as adequate as one that includes food sources that are complete proteins.

    Incomplete proteins are only an issue in very poor areas of developing countries where people might subsist on grains for extended periods of time.

    As for methionine and lysine not being absorbed well from plant foods — absolutely inaccurate!

    Not only, like I just mentioned, are some plant foods complete proteins, but incomplete varieties like beans, lentils, and seeds are rich in methionine, while lysine can be easily obtained from nuts.  Our bodies have no difficulty absorbing those two amino acids from plant proteins.

    On another note, my “red flag” alert about silly food restrictions certainly goes up for Sugar Busters.

    While the book emphasizes dietary patterns that provide sufficient amounts of whole grains, lean protein, healthy fats, and vegetables, I find their placing of bananas, raisins, pineapple, potatoes, and watermelon on the “banned food” list absolutely ridiculous and counter-intuitive.

    Artificial sweeteners are A-okay but a banana gets blamed for obesity and diabetes?  Give me a break.


    You Ask, I Answer: Soy Protein

    100-soy-proteinWhen I was at the gym today, I overheard two guys talking.

    One of them was telling the other that he drinks soy protein shakes since he is lactose-intolerant.

    The other guy told him that is the worst thing he can do, since soy’s amino acids are converted into estrogen by the body, and don’t let muscles grow.

    This didn’t sound right to me, but I figured I would ask you.

    — Tom Dalgers
    New York, NY

    You are absolutely right, Tom.  It doesn’t sound right… because it’s completely false!

    Some basic nutrition and human physiology concepts demonstrate why “guy #2” should not be so quick to dole out his brand of advice.

    Soy, just like all varities of meat, contains all nine essential amino acids.  It is considered a “complete protein,” in that sense (compared to something like whole wheat bread or peanut butter).

    Remember, though, that as long as you eat a balanced diet, it is not detrimental to consume “incomplete proteins,” since the amino acids lacking in whole grains are found in legumes (and vice versa).

    As for the amino acids in soy being converted to estrogen?  Nonsense!  The body produces estrogen from cholesterol, not from amino acids.

    Even if “guy #2” had a momentary lapse in memory and meant to say that the phytoestrogens in soy are converted to estrogen in the body, he would still be wrong.

    If you look at the research literature on soy and testosterone, you will see that the vast majority of studies find no relation between soy intake and decreased testosterone.  The small handful (out of hundreds) of studies that found compromised testosterone levels were using preposterously high amounts of soy protein in their experiments.

    While we’re at it, let me remind you that muscles grow as a result of performing weight-bearing exercises, not from consuming protein.  Although the timing of protein consumption after a workout can help maximize results, the average person (and especially man) in the United States is already consuming, on average, twice the amount of required protein.  Supplementing with additional amounts doesn’t make much sense.

    The protein shake industry has done such a great job convincing people looking to bulk up that they need more protein that the most essential aspect of gaining weight while weightlifting — eating more calories! — is forgotten about by many.


    You Ask, I Answer: Phenylketoneuria/Phenylalanine

    Every time I pick up a pack of gum, I see a warning that says “phenylketoneurics: contains phenylalanine”

    What IS phenylalanine and why would it need to have a warning associated with it?

    I’m concerned because I enjoy chewing gum while I’m working out but haven’t been lately because of this additive.

    Any insight you could give me on this would be really helpful

    — Leigh Simpson
    Clarksboro, NJ

    There is a genetic condition known as phenylketoneuria (PKU) in which people lack an enzyme called phenylalanine hydroxylase (PAH).

    PAH is necessary to convert phenylalanine (an essential amino acid) into tyrosine (a non-essential amino acid).

    Just to be clear: phenylalanine is NOT an artificial additive.

    Without that enzyme, phenylalanine accumulates in the body and, rather than get converted into tyrosine, is metabolized into phenylpyruvate.

    Adults diagnosed with PKU who do not monitor their phenylalanine intake put themselves at great risk for seizures, concentration problems, mental confusion, and impaired memory.

    Pregnant women with PKU need to be particularly careful, as an improper diet will negatively effect the brain development of the fetus.

    Newborn babies are screened for PKU since an inadequate diet (high in phenylalanine) causes irreversible mental disability.

    The only way to treat this is through diet modification; specifically, limiting phenylalanine intake.

    Food sources high in phenylalanine include whole grains, fish, dairy, soybeans, nuts, and dark green leafy vegetables. In a PKU diet, all of these foods must be completely avoided.

    Although some small companies now sell low-protein breads and cookies for the PKU population, most affected individuals rely on prescribed phenylalanine-free protein mixtures and formulas that can be incorporated into their diet.

    Since aspartame also contains high levels of phenylalanine, products containing the artificial sweetener (including diet sodas and sugar-free chewing gum) must carry a warning label.

    The only people who should be concerned with phenylalanine are those with PKU; otherwise, you have absolutely no reason to worry.


    You Ask, I Answer: Tryptophan

    I am writing to you so you can hopefully help me prove a point.

    My cousin claims the reason why people feel tired after Thanksgiving dinner is because of the tryptophan in turkey.

    I say that’s a myth.

    She insists it has been “scientifically proven” that tryptophan makes you sleepy.

    What do you have to say?

    — Lori Narth
    (Location withheld)

    Ah, yes, the “turkey makes you sleepy” myth. Let’s break this one down.

    Tryptophan is one of twenty amino acids (and one of nine essential amino acids which we must get from food.)

    Tryptophan also happens to be a pre-cursor for serotonin (a neurotransmitter) and melatonin (a hormone), which play significant roles in the regulation of sleep.

    That might make you think there is a direct link between the tryptophan in your turkey dinner and your desire to nap a short while later.

    Not so much.

    First of all, although tryptophan is one amino acid in turkey, it is also found in other foods.

    In fact, chicken breast, tuna, soybeans, and beef contain more tryptophan than turkey! Snapper, black beans, and cod are also good sources of this amino acid.

    More importantly, tryptophan is one of many amino acids contained in a Thanksgiving dinner.

    This means tryptophan is competing with other similar compounds for absorption by the brain. Simply put, you aren’t getting enough of it to make you sleepy.

    Research has shown you would have to eat a significant amount of turkey — almost the entire bird! — on an empty stomach to feel any sleep-inducing effects.

    A much more accurate theory for the sleepiness after Thanksgiving dinner has to do with the sheer amount of food eaten.

    With that much food to digest, the body sends as much blood as it can to the intestinal tract, resulting in an energy zap.

    This is the main reason behind the “small meals throughout the day” recommendation — by not overworking your digestive system at any given time, your energy level is more likely to remain steady.

    Remember, too, that most Thanksgiving meals include white bread, mashed potatoes, and cranberry sauce.

    Those are precisely the kind of carbohydrates that make blood sugar levels rise and fall rather sharply, making for a more noticeable “energy crash.”

    It is also a known fact that meals high in carbohydrate increase insulin levels, consequently increasing the amount of serotonin produced by the body.

    I also think people forget that the buildup to such events (traveling to someone’s house, preparing the food, and being socially “on”) can be rather tiresome in and of itself.


    You Ask, I Answer: Whey Protein/Protein Needs

    I was wondering about whey protein powder and your thoughts on protein needs.

    Is whey protein really more “bio-available” or better than other protein sources?

    How much protein does a person need?

    Is more protein necessary for muscle recovery or building after working out?

    Does whey protein improve our immune system?

    — Michael (last name withheld)
    (City unknown), Illinois

    The average healthy adult requires no more than 0.8 grams of protein per kilogram of body weight (if you only know your weight in pounds, divide it by 2.2 to determine the kilogram equivalent).

    The 0.8 grams figure solely represents the daily requirement — you can consume up to 200% of that total and still be within a perfectly safe range.

    It’s always amusing to me to see protein heavily advertised on certain products, almost as if it were a nutrient we were all severely lacking.

    Far from it! The average adult in the United States consumes anywhere from 175 – 200 percent of their daily protein needs.

    Let’s break down this ever-persistent myth that athletes (or any regular person who lifts weights and wants to bulk up, for that matter) need to consume tons of protein.

    Remember, the average adult requires 0.8 grams of protein per kilogram of body weight.

    When it comes to athletes and others engaging in strenuous physical activity, protein needs ARE higher, but we are talking, at most, 1.5 or 1.6 grams per kilogram.

    In other words, their needs fall within the “permissible” 200 percent range (which, again, corresponds to average protein intakes in the United States anyway).

    A few things worth mentioning here.

    Firstly, building muscle has more to do with consuming excess calories and performing weight-bearing exercises that challenge and shock the muscles appropriately.

    Overloading on protein but consuming too few total calories and/or not performing the appropriate exercises at the appropriate intensity levels is completely futile.

    What athletes and people performing strenuous exercise should focus on is protein quality, not quantity.

    This is where biological value comes in.

    Biological value is a term referring to how closely a protein matches the amino acid composition required by the body.

    Complete proteins – all animal-derived ones as well as soy – contain all 8 essential amino acids.

    Incomplete proteins – from vegetable sources – usually lack one or two.

    This is not to say that vegetarians are not getting adequate protein.

    See, Mother Nature is one smart cookie.

    Proof? The amino acid lacking in grains is present in legumes (and vice versa). So, as long as a vegetarian has a diet containing various food groups, their amino acid needs are met.

    In fact, many athletes as well as Olympic, Ironman, and Mr. Universe bodybuilding competitors and winners have been vegetarian.

    Some names? Billie Jean King, Bruce Lee, Carl Lewis, Joe Namath, and Martina Navratilova.

    Back to biological value. If we are speaking about foods, eggs are the absolute best (yes, even better than meat, chicken, and fish).

    Whey protein, however, has an even higher score. So, technically, it is the most bio-available protein.

    Since biological value also tells us the percentage of the protein used for muscle growth and repair, it is no surprise whey protein is the chosen favorite of weight-lifters.

    Again, though, many people fail to realize that protein quality is more important than protein quantity.

    Remember, except for extreme circumstances, protein is not used for energy; carbohydrates and fat are. Too much protein simply ends up being stored as fat.

    So how about nutrition needs after a workout?

    Again, many people immediately think, “protein.” While that is certainly one part, they often forget two other just as crucial nutrients: carbohydrates and water.

    Countless studies have determined that consuming protein AND carbohydrates no more than 30 to 45 minutes after a strenuous (approximately 1 hour) workout are more efficient at muscle recovery than protein alone.

    Think roughly 30 – 50 grams of carbohydrates.

    Another tip: carbohydrates ranking higher in the glycemic index (such as watermelons, dates, potatoes, and cereals) are often preferred during this window of time, since they replenish fuel stores more quickly and aid in muscle repair.

    In regards to whey protein’s effects on the immune system, there is a good body of research showing a link between whey protein consumption and an increase in glutathione levels (a protein that plays a crucial role in human immune systems).

    It is important to note, though, that other foods (spinach, walnuts, cauliflower, avocado, and broccoli, all in their raw forms) also have the same effect.


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