In the first part of this article, I talked about how a diet consistently high in animal proteins over a long period of time, such as a typical bodybuilding diet, can induce a metabolic condition known as acidosis. The negative effect of acidosis on muscle tissue is well documented in scientific studies. One study indicated that normal subjects with experimentally induced acidosis, lost about 360 mmol of nitrogen (the equivalent of about 30 grams of protein) per day. Studies have also demonstrated that acidosis promotes degradation of branched chain amino acids (BCAAs). Seven healthy subjects were studied before and after the induction of acidosis (with 5 days of oral ammonium chloride), and the results indicated that acidosis increased leucine oxidation by 19%! Another study that examined the effect of chronic acidosis on amino acid turnover in rats, found that amino acid oxidation increased by 145% in rats with chronic metabolic acidosis compared to the control group. Meanwhile, Ballmer and colleagues found that chronic acidosis caused negative nitrogen balance, and decreased albumin synthesis in humans by 24 %!

All of this may come as a surprise to many bodybuilders, who often think that more, and more, and yet more protein is better. To a large extent, they are right. If you want to be huge and muscular, you must eat a lot of protein. Serious bodybuilders don't have a choice, as your body will not be able to build large amounts of new muscle tissue without enough dietary protein. So the question is what to do about this apparent paradox?

Well, it may interest you to know that, while acidosis may promote negative nitrogen balance and loss of muscle, studies have also indicated that alkalosis, where metabolic pH is more basal than acidic, does the opposite. For those not familiar with the pH scale, a lower number indicates more acidity, and a higher number more alkalinity. An in vitro study examined how extracellular acidification affects cellular protein turnover. Compared to a pH baseline of 7.4, protein synthesis decreased 29% at 7.2, but increased 129% at 7.6. That's not all. Insulin stimulated protein synthesis at all pHs, but at pH 7.4 the insulin-induced increase in protein synthesis was less than the rate at pH 7.6, without insulin! If you want evidence in vivo, a recent study examined the effects of alkalosis on protein synthesis of trauma patients in intensive care. Alkalosis was induced in the patients through hyperventilation. The results indicated that muscle protein synthesis was elevated during hyperventilation, and that experimentally induced alkalosis increased protein synthesis in muscle tissue by 32.6%.

Interesting stuff? You bet it is! But here is the best part…..studies have indicated that dietary methods can be very effective at mitigating the negative effects of acidosis. One study found that correction of acidosis in acidotic patients via supplementation with sodium or potassium bicarbonate was able to inhibit protein breakdown, and to increase nitrogen retention. Another study examined the relationship between dietary potassium (an alkaline nutrient) and lean mass in 384 men and women. Results of the study indicate that a higher intake of alkaline foods such as fruit and vegetables was associated with greater lean body mass in older men and women. In other words, the alkaline diet appears to favor greater muscle mass.

Aside from things like nitrogen balance and protein synthesis, I mentioned in the first part of my article, that acidosis can decrease serum IGF-1 (insulin-like growth factor) levels, and make the body less receptive to GH (growth hormone). Here too, the evidence suggests that this can be reversed by dietary intake of alkaline nutrients. Researchers found that metabolic acidosis, induced by administration of ammonium chloride, decreased serum IGF-1 concentration by 26,6 %. But in contrast, another study found that the correction of acidosis by oral citrate administration partly corrected IGF-1 levels, and reversed GH insensitivity. In another study, neutralization of metabolic acidosis with potassium bicarbonate increased 24 hour GH secretion by 11 %. Potassium bicarbonate has also been associated with increased levels of IGF-1.

The upshot of all this is that, if you want to maximize your muscle, you must balance the acid producing animal proteins, with more alkaline producing foods. Generally these tend to be vegetables and fruits, but let's take a closer look at various foods.

When foods are digested, each component of that food will present itself to the kidneys as either an acid-forming compound or a base-forming one. Acid forming micronutrients include things like chloride, phosphorous, sulfates, and other organic acids, while base forming nutrients include sodium, potassium, calcium, and magnesium. Differences in the relative amounts of acid and base precursors absorbed by the digestive system will determine the metabolism's net endogenous acid production (NEAP). Scientists have looked for various techniques to estimate NEAP, and probably the best method to date was developed by Remer and Manz. By analyzing the specific micronutrients in a given food, they were able to determine something called Potential Renal Acid Load (PRAL), a single-number assessment of the overall acidifying or alkalizing effect of a particular food. They then combined PRAL (which is a diet dependent measure) with organic acid excretion (which is independent of diet) to estimate NEAP.

The PRAL score of a given food depends on more than just the micronutrient components of the food. Things like absorption rates, generation of sulfates from amino acids, and a variety of other factors are taken into account. I won't bore you with the details of the calculation method, but the important thing is we CAN estimate the net acid or base producing load of a given food using PRAL as a comparative measure. The more negative the PRAL, the more alkaline the food. If you add the PRAL values for all the foods you eat, you get the net acid or alkaline load for the day.

So, let's look at the PRAL scores of some common foods:

*PRAL= PRAL = [0.49 protein (g)] + [0.027 Cl (mg)] + [0.037 P (mg)] – [0.021 K (mg)] – [0.026 Mg (mg)] – [0.0413 Na (mg)] – [0.013 Ca (mg)]; Resources: www.bitterpoison.com, www.goutpal.com and Remer T, Manz F. Potential renal acid load of foods and its influence on urine pH. J Am Diet Assoc 1995;95:791-797

You can see that the typical western diet, and especially the typical bodybuilding diet, generally based on foods with a high positive PRAL score (eg: chicken breast!), is bleeding from many wounds. To counteract the effects of acidosis, you have to eat more alkaline. This means including a lot more base-forming foods (ie: foods with negative PRAL scores) in your diet. Which foods should you choose? Well, look at the table and you will know the answer...you must eat more veggies!

Sorry guys. I know what you’re thinking……“All this research, all this science, all this investigation, and it boils down to what my mom told me when I was six years old?!” Well, basically, yeah!

Anyway, the truth is that it’s not quite that simple. Like anything, PRAL has limitations. It is not the “Holy Grail”, but at least it provides a decent compass, and is probably the simplest scientific method available at this time. The other thing to consider is behaviour. I’m one of the biggest advocates of increased vegetable consumption (yes, it’s true….I admit it….I’m in cahoots with your mom), but I also know that it is possible to overdo the alkaline diet thing. Let’s face it, hardcore bodybuilders are extremists. When we do something, it tends to be on an extreme level, and we don’t know the meaning of moderation, or the golden mean.

For example, take the case of the 20 year old amateur boxer. Trained every day, ate very healthy, didn’t smoke, drink, or take any recreational, or performance enhancing drugs. Yet he reported to a clinic with problems like a gradual decline in muscular and physical activity, a drop in sexual desire, and progressive erectile dysfunction. After much investigation, it turned out the problem was his diet! For more than a year, he had daily consumption of half a kilo of carrots, half a kilo of broccoli, and large portions of lettuce, tomato, cabbage and garlic. These vegetables are all very rich in carotenoids. Carotenoids are vital for good health, but you can overdo it, and this boxer showed all the signs of carotene overdose. Two weeks, after normalization of his diet, carotene B levels were still at the upper end of the normal range, and androgen secretion and sexual response did not return to complete normality for a full nine months after diagnosis, and initial treatment.

The take home message is balance, and a proper diet plan. Veggies are vital for good health, and by counteracting acidosis, very useful in maximizing muscle growth, but we must find the right balance. Stay tuned, as in future articles, I will outline specific diet plans for maximizing muscle!

References

Remer T, Manz F. Potential renal acid load of foods and its influence on urine pH. J Am Diet Assoc 1995;95:791-797.

Tomas C Welbourne: Increased plasma bicarbonate and growth hormone after an oral glutamine load. A J Clin Nutr 1995;61:1058-61.

P. L. Greenhaff, M. Gleeson and R. J. Maughan: The effects of dietary manipulation on blood acid-base status and the performance of high intensity exercise. European Journal of Applied Physiology. 1987 56(3) 331-337

P E Ballmer, M A McNurlan, H N Hulter, S E Anderson, P J Garlick, and R Krapf: Chronic metabolic acidosis decreases albumin synthesis and induces negative nitrogen balance in humans. J Clin Invest. 1995 January; 95(1): 39–45.

D. Reaich, S. M. Channon, C. M. Scrimgeour and T. H. Goodship: Ammonium chloride-induced acidosis increases protein breakdown and amino acid oxidation in humans. Endocrinology and Metabolism, 1992 263(4):E735-E739

Dawson-Hughes B, Harris SS, Cegila L: Alkaline diets favor lean tissue in older adults. Am Journ Clin Nut. 2008 87(3): 662-665

Vosswinkel et al.: Hyperventillation increase muscle protein syntesis in criticaly ill trauma patients J Sorg Res 91: 61-64

B. K. England, J. L. Chastain and W. E. Mitch: Abnormalities in protein synthesis and degradation induced by extracellular pH in BC3H1 myocytes Am J Physiol Cell Physiol 1991 260 (2): C277-C282,

B. K. England, J. L. Chastain and W. E. Mitch: Abnormalities in protein synthesis and degradation induced by extracellular pH in BC3H1 myocytes Am J Physiol Cell Physiol 1991 260 (2): C277-C282,

May RC, Masud T, Logue B, Bailey J, England BK: Metabolic acidosis accelerates whole body protein degradation and leucine oxidation by a glucocorticoid-dependent mechanism. Miner Electrolyte Metab. 1992;18(2-5):245-9

May Rc; Bailey Jl; Mitch We; Masud T; England Bk: Glucocorticoids and acidosis stimulate protein and amino acid catabolism in vivo. Kidney international. 1996 49(3): 679-683

May Rc; Bailey Jl; Mitch We; Masud T; England Bk: Glucocorticoids and acidosis stimulate protein and amino acid catabolism in vivo. Kidney international. 1996 49(3): 679-683

Rajan, Vik; Mitch, William: Muscle wasting in chronic kidney disease: the role of the ubiquitin proteasome system and its clinical impact Pediatric Nephrology, 2008 23 (4): 527-535(9)

Brüngger M, Hulter HN, Krapf R: Effect of chronic metabolic acidosis on the growth hormone/IGF-1 endocrine axis: new cause of growth hormone insensitivity in humans. Kidney Int. 1997 Jan;51(1):216-21.


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