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Invincible Immunity

Posted Jan 11 2009 2:48pm

Invincible Immunity

by Eric Cressey

Of all the lousy things that can happen, this has to be one of the worst. Imagine…You’ve just completed the most successful bulking cycle of your life, adding twenty pounds of mass; you’re on top of the world. Now, all you have to do is train properly and eat plentifully in order to solidify your gains. With your knowledge of diet and training, it should be a snap. Then everything hits the fan…

Your girlfriend is so proud of you for making such great gains and transforming your physique that she can’t keep her hands off of you. The day before, she had shared a soda with a friend who had just come from the gym. That friend had taken a sip from the water fountain at the gym and accidentally touched her lips to the spout. Ten minutes earlier, that skanky “human sweat gland” guy who spends five hours on the elliptical cross trainer each day had just made out with that same water fountain. That morning, he had kissed his wife goodbye before leaving for his job at the DMV. That wife is the teacher of a kindergarten class. Incidentally, that class happened to be riddled with the flu, and some kid had blown chunks all over her nice new blouse the day before. Sure she cleaned it up, but she still wound up with the flu. Thanks to this incredibly unlikely downward spiral, you are now home sick from work, pitying yourself as you watch the same episode of Sportscenter eight times in a row. All the while, you’re thinking about how you would much rather be deadlifting like a madman and showing off your gains at the gym!

Unfortunately, you cannot go back in time to prevent yourself from coming down with the flu. Although it may be beneficial to look back and figure out if there was anything you could have done to strengthen your immune system ( avoiding overtraining, paying attention to post-workout nutrition, taking certain supplements, getting plenty of sleep, etc.), you need to focus on the task at hand: beating the flu! You see, bodybuilders, powerlifters, and other athletes have to take into account how sickness affects performance and physical appearance, whereas normal folks just worry about “getting rid of their sniffles.”

Before we get to the specifics, though, I should mention that the term “flu” that we so often use is short for influenza. Influenza (also known as Grippe or Grip) is really only one of several common kinds of viral respiratory infections. Also including on this list are the common cold (upper respiratory infection or acute coryza), pharyngitis, laryngitis, tracheobronchitis, and viral pneumonia (1). Regardless of the clear differences in the nuts and bolts of each infection, they are generally all lumped together and called the flu by the general public. While this oversimplification is erroneous, the human immune system must be strong to prevent and in many cases overcome any type of infection. And, if you’re anything like me, you detest the idea of getting loaded up on medications, sugary cough syrups, and lozenges just because your nose is running faster than a sprinter with a rocket up his butt. All that being said, let’s get to work on finding a universal approach to maintaining your gains and getting back to optimal health as soon as possible.


Proper diet seems like a no-brainer, right? One would think so, but I’m constantly amazed at how people vehemently adhere to this primitive urge that tells them to stuff themselves full of crap foods just because they feel like crap! These crap foods are usually “comfort” foods: Mom’s cookies, white toast with cinnamon, sugar, and butter, hot chocolate, a whole gallon of ice cream?. These foods may have made you feel better as a kid when they were used to take your mind off the “boo-boo” on your knee, but they’ll only make thing worse when you are a sick adult. They might make you feel all warm and toasty on the inside, but they’ll quickly make you soft and fluffy on the outside if you overindulge.

So what should you eat and what should you avoid? For starters, remember that total calories are of foremost importance. Don’t fall into the trap of dropping calories too low out of fear of gaining fat while “on the shelf.” Instead, it’s important to assume the mindset of maintaining the status quo physique-wise while bringing the immune system up to par. If you gain a little fat, don’t sweat it. Remember, it’s a lot easier to shed a little fat than it is to regain a few pounds of lost muscle. In reaching your daily caloric goal, as usual, spread your intake out over six smaller meals. Maintenance caloric intake is highly variable, so rather than multiplying your body weight by a certain number to find your target, base your intake on slightly below (100-150 calories) what you would take in on a normal rest day. This decrease should account for the extra time spent on the couch or in bed.

Specific macronutrient recommendations are also of little value in this instance due to individual variations in terms of carb tolerance. As such, adhere to your typical macronutrient ratios with the only exception being a slight reduction in carb intake to compensate for the diminutive calorie reduction and reduced training effect. Furthermore, make sure that you keep protein high (1-1.5g/lb lean body mass) in order to remain in positive nitrogen balance and stop muscle protein catabolism in its tracks. From all our cutting cycles, we’re all well aware that protein needs increase during times of stress, and sickness is certainly one of those times. In a study of critically ill children in hypermetabolic and catabolic states, researchers found that a higher protein intake was associated with positive nitrogen balance, whereas a low intake (with total calories held constant) led to a continued state of negative nitrogen balance and muscle protein catabolism (2). A big steak probably won’t sound too appealing when you’re sick, though, so low carb protein powders (such as Xtreme Ultra Peptide), cottage cheese, omelets, and other “easy to get down” protein sources might turn out to be your best friends.

Next, only consume low-glycemic carbs. When you’re sick, your body isn’t primed for sucking up simple sugars like it is when you’ve just completed a training session. So, the typical bodybuilding “no-no” foods should be even more off-limits than usual. Your best bet is to focus carb intake early in the day when muscle cells are most receptive to storing glycogen.

Keep fats (especially healthy fats) up as well - possibly at the expense of carbohydrates. In the aforementioned study of critically ill children, fat was used preferentially for oxidation. Meanwhile, a high carbohydrate intake was associated with lipogenesis (fat formation) and decreased fat oxidation (2). Thirty percent of total calories is a good figure in order to support endogenous testosterone and overall energy levels (as fat is the primary source of energy at rest). Your body will be forming plenty of new immune cells as you fight off sickness, and fatty acids constitute an important component of each new cell membrane. Therefore, in order to give the body the best raw materials available, make sure that you’re getting plenty of omega-3 fatty acids.

However, don’t fall into the trap of overdoing the omega-3s or fat in general; very high fat diets are associated with impaired lymphocyte (one of the five kinds of leukocytes, or white blood cells) function (3). Furthermore, while fish oil has proven effective in enhancing immune function in certain clinical situations (e.g. rheumatoid arthritis, ulcerative colitis) and in animals, studies of healthy humans are yet to yield consistently favorable results to substantiate the claim that omega-3s enhance immunity (4). As such, there does not appear to be any greater benefit (at least not yet) to increasing omega-3 PUFA intake during times of sickness. Simply stick to your normal intake levels, relying on healthy sources such as fish oil and flaxseed oil for your supplemental fat intake.

The last dietary concern that warrants mention is water intake. You might think that because you aren’t training, you don’t need to worry much about pushing the H2O- big mistake. The body loses a significant amount of fluids each day independent of training. We’re constantly losing water as we dissipate heat through our skin and in our breathing without even knowing it. Factor in increased mucus production, the sweating that may be associated with a fever, the fact that your body is constantly constructing new cells (especially during sickness), not to mention your higher protein intake, and you can begin to realize the importance of really emphasizing water intake. Shoot for at least one gallon (preferably more) of water daily.

All these considerations in mind, I highly recommend you pick up a copy of Precision Nutrition from Dr. John Berardi.  His information is fantastic, highly effective,  and presented in a user-friendly format.


First and foremost, be sure to get a flu shot each fall. The optimal time to do so is mid-September through November, as it takes at least a week for the shot to really kick into protective-mode. If you need proof that the influenza vaccine is worth the fee (if you even have to pay for it), look no further than a study conducted on a Brazilian airline company’s employees. As I’m sure you can imagine, flight attendants and those in related roles are a population segment that is extremely susceptible to the flu due to their interactions with so many customers (often in confined spaces). Prior to flu season, each of 813 employees received either an influenza vaccination or a placebo. Seven months later, the employees who had received the vaccines showed 39.5% fewer episodes of flu-like illness than the placebo. Additionally, the vaccine group was absent from work due to sickness 26% less often than the placebo group (5). From a weight-training standpoint, that 26% corresponds to a lot of missed training sessions. In addition to the flu shot and your regular multivitamin, you should definitely include the following:

Vitamin C

Vitamin C (ascorbic acid) is the first immune-booster that comes to mind. A vital component of every cell in the human body, ascorbic acid is perhaps most notably found in high concentrations in leukocytes (white blood cells). The leukocytes are constantly being produced in the bone marrow as safeguards against bad stuff like cottage cheese gone sour, reruns of those obnoxious Subway commercials with Jared, curling in the squat rack, and, oh yeah, infections. During infection, in order to prevent oxidative damage, the vitamin C within the leukocytes is used up faster than a post-training shaker bottle full of Relentless (4)! Thus, it should come as no surprise that reduced leukocyte vitamin C levels are associated with less than optimal immune function. (6) In the worst vitamin C deficit scenario, scurvy, the immune response is entirely inadequate (and sometimes nonexistent) in each of the many components of the immune system. In fact, overall vitamin C status is often measured via an assessment of levels in the leukocytes (4).

In terms of preventative supplementation, a true consensus has not yet been met regarding the efficacy of vitamin C in reducing the occurrence of common colds. Several respected studies have found that Vitamin C supplementation is of little value in preventing the common cold (7), whereas others have reported decreased incidences of reported common cold infection among individuals who received large doses of a vitamin C supplement (8,9). However, other studies have verified the assertions that supplementation with vitamin C improves several aspects of the human immune response, effecting positive changes in proliferation and/or function of in three of the five types of leukocytes: lymphocytes, neutrophils, and monocytes (10-16).

Adequate vitamin C status is often defined as “a circulating pool of 1500mg” (7). Due to the fact that water-soluble vitamins like vitamin C are not stored by the body as well as fat-soluble vitamins, ascorbic acid must be continuously replenished through diet and supplementation. Doses of up to 10g per day have been used in numerous studies without serious toxicity symptoms. The side effects of such high consumption may include diarrhea and, in serious cases, kidney stones or urate crystals (due to increased uric acid release in the urine). Antonio and Stout state that these risks have “been greatly overstated” (7). Based on the available literature, I recommend 2-2.5g of supplemental vitamin C daily during normal training conditions and 4-5g daily during flu-like symptoms and times increased of training stress. Also, be sure to spread your intake throughout the day in 500mg doses. Dosages of 500mg are proven to increase cellular ascorbic acid absorption by up to 40%, whereas dosages greater do not increase this absorption (17).

Vitamin E

Perhaps as important as vitamin C is Vitamin E, which works synergistically with selenium in tissues to reduce lipid membrane damage by reactive oxygen species (ROS) during infections (4). Vitamin E has proven effective in improving various parameters of the immune function, including enhanced lymphocyte production, improved antibody response to vaccine, reduced pulmonary viral titers (a measure of virus prevalence in respiratory infections), and “preventing an influenza-mediated decrease in food intake and weight loss” (18-20). No decrease in food intake? Maybe that steak won’t sound so bad after all!

All that being said, even the slightest deficiency in vitamin E can easily compromise one’s immune response. And, the current RDA of 30 IU is barely adequate in preventing deficiency in sedentary, normally healthy individuals, let alone in athletes, the elderly, and the sick and diseased. Granted, one may derive a considerable amount of vitamin E from diet alone, but in order to receive sufficient vitamin E to attain an enhanced immune benefit, one must supplement in excess of the RDA (especially on low-fat diets). Vitamin E is recognized as one of the least toxic vitamins, although one may experience some minor symptoms (nausea, diarrhea, muscle weakness) with very high dosages (7,21). As such, 800-1200 IU throughout the year (regardless of whether you’re sick or healthy) is an optimal approach.


Glutamine is well known as the most abundant amino acid in the human body (including both the plasma and tissue pool). In fact, the intramuscular free amino acid pool is more than 60% glutamine, and the glutamine in skeletal muscle accounts for about 90% of the body’s total glutamine pool. Although over 40% of the body’s glutamine is devoted to fueling the GI tract, this amino acid also plays a role in the functioning of many other parts of the body, including the liver, brain, muscles (duh!), hair follicles, kidneys, and - you guessed it - the immune system (7,22-24). Adequate levels of glutamine are necessary to ensure optimal proliferation and function of lymphocytes, macrophages, and neutrophils (25,26).

Traditionally, because the body can synthesize glutamine endogenously (mostly in the muscle tissue), it has been classified as a nonessential amino acid. However, this classification is made under the assumption that the body is not enduring a stressful physiologic trauma such as sickness (23). Many researchers have now begun to classify glutamine as a conditionally essential amino acid during times of sickness, infection, and malnutrition. Because glutamine is a crucial substrate for a variety of metabolic processes, it is only logical that the body requires increased amounts of the amino acid during infection in order to “bolster” the immune system while maintaining normal physiological functioning (24,26).

Unfortunately, as you can see in many cancer patients, the body’s response to infection, injury, and stress is protein catabolism. Initially, plasma glutamine levels are depleted. Next, in order to sustain its metabolic processes and replenish plasma glutamine levels, the body takes glutamine from skeletal muscle. Normally, this isn’t a problem, as skeletal muscle glutamine synthesis matches glutamine release. However, during times of stress, there is a problem: numerous organs, including the liver and bowel, show marked increases in glutamine uptake during infection. These increases, in combination with the needs of the immune system, GI tract, and the regular metabolic processes, cause glutamine release from skeletal muscle to exceed glutamine synthesis. In fact, skeletal muscle glutamine release may double during infection (23,27). In summary, during infection:

1. Glutamine use increases
2. Glutamine supply decreases
3. A concentration gradient across the muscle cell membrane cannot be reached (23)
4. Your beloved quad sweep becomes fuel for your GI tract and, essentially, your body’s lunch.

Think about it for a second: when you’re sick, is your body going to care more about ensuring appropriate internal organ functioning or maintaining sleeve-splitting biceps? Luckily, numerous studies have proven that exogenous glutamine can help to: maintain positive nitrogen balance (and glutamine levels in skeletal muscle), increase plasma glutamine levels, prevent decreases in ribosomal concentrations, improve muscle protein synthesis rates, and enhance immune function (through such mechanisms as encouraged lymphocyte proliferation) (7, 28-32). Also, let’s not forget that glutamine?s “immunoenhancing” effects make it an effective year-round, recovery-promoting supplement (albeit in smaller doses) for hard training athletes who are more susceptible to infection, especially during and shortly after periods of intensive training (7,33,34). Glutamine supplementation is also associated with increased plasma GH concentration, which may also assist in immunity (7,35). During illness, shoot for 0.35-0.4g glutamine per kg body weight, and spread your intake out throughout the day in 3-5g doses. Based on the published clinical studies and for absorbability reasons, I recommend glutamine peptides. L-glutamine (free form), however, tastes better, generally costs less, and will also yield favorable results. Personally, I’ll stick with peptides, but it’s your call; just make sure to get it in you in some form!


Although most people primarily associate zinc with growth and development, this trace mineral also plays a crucial role in proper immune function. A deficiency of zinc relates to diminished immune response, including low T- and B-cell (the two broad categories of lymphocytes) counts in bone marrow due to decreased proliferation, and reduced antibody production (just to name a few). In some mice, only thirty days of inadequate zinc intake caused an 80% reduction in immune capacity. As such, it should come as no surprise that zinc deficiencies are prevalent in numerous immune system-stressing chronic illnesses, including HIV, renal disease, and alcoholism (4,36).

While the complications of zinc deficiency are well established, studies on the benefits of zinc supplementation in enhancing immune function have yielded mixed, but mostly favorable results. Numerous studies have found that zinc supplementation initiated upon the onset of a cold or upper respiratory tract infection decreases the sickness’ duration and severity (7,37-39). In a study of twenty burn victims, fewer pulmonary infection rates and shorter hospital stays were observed in patients who received a trace mineral supplement that included zinc (40). Meanwhile, zinc supplementation in long distance runners prevented the typical increase in reactive oxidative species normally seen with endurance activity (41).

In terms of preventative supplementation, researchers found that of 609 school children that were given either a zinc supplement or a placebo, those who supplemented with zinc had 45% fewer acute lower respiratory infections over the 120-day study (42). If you take nothing else from all these studies, at least walk away from this article cognizant of how important sufficient intake is, especially for athletes (who are more likely to be deficient than the general population). While high-dose supplementation can actually lead to immunosuppression, moderate supplementation throughout the year with slightly increased dosages beginning at the onset of flu- or cold-like symptoms is an effective and safe supplementation approach (7). During sickness, take at least 25mg zinc (but not more than 100mg) per day. An optimal approach would be to get this supplemental intake in the form of a ZMA supplement, as it will enable you to meet your zinc needs while increasing anabolic hormone levels, improving recovery, and promoting deep, restful sleep.

Miscellaneous: the other stuff

Here are a few other supplements that are often thrown into the immunity discussion, but will probably not be worthwhile additions to your immune effort:

Vitamin A (preformed vitamin A is known as beta-carotene): Although vitamin A is of unquestionable importance to proper immune functioning, there is no definitive evidence to suggest that supplemental vitamin A offers additional benefits over normal dietary intake, especially in those with already adequate status. Excessive vitamin A intakes have been associated with suppression of T- and B-cell function, thus causing a greater susceptibility to infection. Toxicity can also become an issue with higher intakes. Vitamin A deficiency is very uncommon in wealthier nations. As such, if you feel that you need to get more beta-carotene than you diet alone provides, make sure to select a multivitamin with at least 5000 micrograms (4,7).

Echinacea: Although a few studies have emerged that show slightly (and relatively insignificantly) shorter respiratory tract infection durations in patients treated with echinacea, most have demonstrated that the herbal product has little or no effect on preventing and treating sickness. This uncertainty is complicated by the fact that there are nine species of the plant, different parts (leaves, stem, roots, flowers) of the plant can be used, and different forms are available (e.g. powder, liquid extract, capsule). Essentially, even if echinacea was definitively proven effective, an argument would still exist over which species, form, and delivery produces the best results. At this point, there is not enough evidence to recommend echinacea as a worthy supplement (7,43-45).

Arginine: This nonessential amino acid has shown promise in improving immune response and wound healing via improved lymphocyte production in individuals with compromised health status. Other studies, however, have shown that arginine supplementation is of no benefit in attempting to enhance the immune response, especially in healthy individuals (7). Given that some clinical trials use upwards of 20g L-arginine per day (mostly without appreciable immunity-related results), forty capsules per day seems like far too risky an investment even if you enjoy being a human guinea pig. Then again, even if you do decide to give arginine a try, be careful; excessive intakes can actually blunt the immune response (46).


An adequate amount of sleep during sickness is of the utmost importance. The old “8-hours at night” recommendation still holds true…as a minimum. You should also be shooting for a nap or two during the day. It seems like a no-brainer to say that you shouldn’t be training when you’re sick, but I’m constantly amazed at how many people still go the gym in spite of their wheezing, sore throats, and aches. Before you stumble off the couch and over to your local gym, ask yourself if your body could really recover from a heavy training session if it hasn’t even recovered from the flu. The answer should be a resounding “NO!” If it isn’t, maybe it will help to think about how your decision to go train will impact others; you’ll probably make half the people in the gym sick just like the “human sweat gland” did to you. Stay home, if not for your own sake, then for the sake of everyone else who enjoys his or her health and visits to the gym. Get over the flu and then get back to the gym!


There you have it: a comprehensive approach to getting back to the gym as soon as possible. To recap:

1. No comfort foods
2. Maintenance calories (factoring in reduced activity level)
3. Normal protein intake
4. Slightly reduced carb intake, consisting of low GI carbs only
5. Normal healthy fat intake
6. Regular Multivitamin
7. 4-5g vitamin C in 500mg doses throughout the day
8. 800-1200 IU vitamin E in 400 IU doses throughout the day
9. 0.35-0.4g glutamine peptides/kg body weight in 3-5g doses throughout the day
10. ZMA supplement (or zinc equivalent providing 25-100mg/day)
11. No training until symptoms are gone
12. R&R

It might not sound as appetizing or heart-warming as a bowl of chicken soup, but it beats Nyquil…


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