Re: Acid-base balance

[Guest guest]

Date: Sun Jan 13, 2002 9:22 amSubject: [CR] _The Paleo Diet_ by Loren Cordain crsociety/message/16578 Khurram wrote: "Watch out for acid-base imbalance: "Cordain stresses one eat LOTS of alkaline-rich foods (veggies and fruits) - always good advice! This is due to the fact that the consumption of meats, fish and eggs produce a net acid load, which causes one to excrete calcium in their urine. The acid imbalance is exacerbated if one consumes grains and dairy, not to mention the chloride from salt (or salt-enriched foods). Veggies and fruits will balance the equation if and only if one maintains a low-salt, dairy/grains/legume-free diet. In Appendix A (p. 213), there is an excellent chart comparing acid-base values of common foods." The chart shows a relatively small number of foods and it does not distinguish between the values they assume in various forms in which they are eaten. Cabbage can be eaten raw, cooked, or fermented. Searching the web, I found another chart listing the average potential renal acid loads (PRAL) of certain food groups and combined foods. This chart is also limited. For example, it lists a single value for all fruits and juices, excluding dried fruit, which has no listing. http://sun.science.wayne.edu/~bio340/StudentPages/Shuster/STRONGBO.html The following acid/alkaline food chart takes a slightly different perspective. It lists veggie alkalinity according to whether they are leafy greens, aboveground, or belowground. He also explains that excessive amounts of any food may produce the opposite effect. (Coffee is listed as being mildly alkaline. Cordain lists coffee as an acid food. The quantity consumed determines the effect). Paradoxically, he lists lemon juice as alkaline-forming while vinegar is acid-forming. http://www.drlam.com/opinion/acidic_body.cfm "The main determining factor", writes Dr. Robbins, a Medical Doctor, a Doctor of Chiropractic and Doctor of Naturopathy, "of alkaline is the organic minerals. One can equate organic minerals with alkaline for better understanding. Foods are of two types, acid or alkaline. This refers to the ash value of a food. (Meaning the type of residue that remains after the food is digested and processed). Is it acid, or is it alkaline? If there is an acid residue (inorganic acids), the body must neutralize this acid to keep the blood from getting acid. The acid is neutralized with alkaline." He draws a finer distinction between various fruits and veggies, and in the different forms in which they are eaten. Cooked veggies, for example, are listed as producing acid ash, while raw veggies form an alkaline ash. (He apparently assumes that the cooking water, containing leached minerals, is discarded after cooking). ACID ASH ALKALINE ASH SOME RAW FRUITS AND VEGETABLES (cranberries, blueberries, plums, prunes, squash) RAW FRUITS WHOLE GRAINS - COOKED DRIED FRUITS OVERCOOKED FRUITS / VEGGIES FROZEN FRUITS / VEGGIES DAIRY PRODUCTS (cheese, eggs, milk, etc) LIGHTLY STEAMED FRUITS & VEGGIES SUGAR and REFINED GRAINS RAW NUTS (almonds, pecans, cashews, etc.) WHITE MEAT (fish, fowl) Raw, Rare, Well Done SPROUTED GRAINS RED MEATS (beef, pork, mutton) Raw, Rare, Well Done HERBS, SPICES, CONDIMENTS, SPICY FOODS (garlic, hot peppers, onions, horseradish, etc.) FRIED FOOD, COFFEE, TEA, SALT, ALCHOHOL DRUGS & MEDICATIONS, TOBACCO. http://www.healthfree.com/nutrition/robbins/acidalk.htm A raw foods website explains that "[m]ost raw-foods diets are predominantly alkaline forming foods, though many fermented foods (raw sauerkraut, seed cheese, raw pickles, etc.) are very acid forming. Sprouting and soaking reportedly reduce the acidity of seeds and nuts. " http://www.living-foods.com/articles/acidalkaline.html Cordain asserts that osteoporosis, high blood pressure, stroke, kidney stones, asthma, exercise-induced asthma, stomach cancer, insomnia, and air and motion sickness develop because of a dietary acid-alkaline imbalance (p.87). He encourages us to get 55% of our calories from lean protein and the balance from fruits, veggies and healthful oils. He maintains that we should eat a diet with a net alkaline load. Since burning fat produces neither an acid ash nor an alkaline ash, all of the alkalinizing from food has to come from fruit and veggies (p.22). (Somewhat confusingly, the previous page claimed that the paleo diet consisted of 19-35% protein). "Acid," according to the Gale Encyclopedia of Medicine, "is a natural by-product of the breakdown of fats and other processes in the body; however, in some conditions, the body does not have enough bicarbonate, an acid neutralizer, to balance the acids produced. This can occur when the body uses fats for energy instead of carbohydrates. Conditions where metabolic acidosis can occur include chronic alcoholism, malnutrition, and diabetic ketoacidosis. Consuming a diet low in carbohydrates and high in fats can also produce metabolic acidosis. "Metabolic acidosis is suspected based on symptoms, but is usually confirmed by laboratory tests on blood and urine samples. Blood pH below 7.35 confirms the condition. Levels of other blood components, including potassium, glucose, ketones, or lactic acid, may also be above normal ranges. The level of bicarbonate in the blood will be low, usually less than 22 mEq/L. Urine pH may fall below 4.5 in metabolic acidosis." http://www.findarticles.com/cf_dls/g2601/0008/2601000894/p1/article.jhtml This raises some intriguing questions: Is burning fat instead of carbs for energy desirable if it leads to an acid-base imbalance? (My workout regimen is in the fat-burning intensity range). Can a conscientious CRONie unwittingly develop low-grade systemic metabolic acidosis? Is a low-grade metabolic alkalosis the optimal acid-base state for humans as Cordain and a recent study [1] recommend? Has anyone had a urinalysis done showing an acidic pH or a high serum uric acid level? (Testing one’s acid-base level would seem to be sine qua non for anyone with osteo angst). Some of the options to increase the alkaline load are: Eating more dark green leafy veggies. Eliminating the least alkalinizing veggies. This would include asparagus (?), broccoli (-1.2), green peppers (-1.4), mushrooms (-1.4), and onions (-1.5). OTOH, restricting nutritious food from the diet to solve one problem may contribute to another problem. Focusing on less acid-producing protein sources. With the exception of ultra-acidifying cheese, protein is all in the +7 to + 10 range. This is not enough of a difference to be worth eliminating protein sources. The same study [1] suggested that taking potassium supplements is would correct the imbalance. However, the study participants were Ad Libers who don’t eat the typical high fruit, high veggie, low sodium CRONie diet. Besides, this could increase the risk of an electrolyte imbalance. Protein and the bioavailability of the individual nutrients in the diet also have to be considered. Simply eating potassium-rich fruit & veggies is not the complete answer [2]. Using Cordain's table, broccoli (-.8) has 325mg K, tomatoes (-3.1) have 222mg K, while celery (-5.2) has 287K and spinach (-14) has 558mg K. With the exception of spinach, I see no parallel between the alkaline value and the K content. [1] Eur J Nutr 2001 Oct;40(5):200-13 Diet, evolution and aging--the pathophysiologic effects of the post-agricultural inversion of the potassium-to-sodium and base-to-chloride ratios in the human diet.Frassetto L, RC Jr, Sellmeyer DE, Todd K, Sebastian A.University of California, San Francisco 94143, USA.…. Our group has shown that contemporary net acid-producing diets do indeed characteristically produce a low-grade systemic metabolic acidosis in otherwise healthy adult subjects, and that the degree of acidosis increases with age, in relation to the normally occurring age-related decline in renal functional capacity. We also found that neutralization of the diet net acid load with dietary supplements of potassium bicarbonate (KHCO3) improved calcium and phosphorus balances, reduced bone resorption rates, improved nitrogen balance, and mitigated the normally occurring age-related decline in growth hormone secretion--all without restricting dietary NaCl. Moreover, we found that co-administration of an alkalinizing salt of potassium (potassium citrate) with NaCl prevented NaCl from increasing urinary calcium excretion and bone resorption, as occurred with NaCl administration alone…. We argue that any level of acidosis may be unacceptable from an evolutionarily perspective, and indeed, that a low-grade metabolic alkalosis may be the optimal acid-base state for humans.PMID: 11842945 [PubMed - in process] [2] Eur J Nutr 2001 Oct;40(5):214-20 Influence of nutrition on acid-base balance--metabolic aspects.Remer T.Research Institute of Child Nutrition--Forschungsinstitut fur Kinderernahrung--Department of Nutrition and Health, Dortmund, Germany. remer@...RESULTS: The paper shows that the diet-induced generation of acidity and alkalinity is not only determined by the metabolism (oxidation) of sulfur-containing amino acids and organic acid anions of alkali salts, respectively. The intestine is also directly involved in the generation of food-derived acid or alkali loads which is due to the considerably different intestinal absorption rates of relevant food components, i. e., protein and minerals. Further analyses of the interrelation between diet and acid-base status revealed that increasing protein intake (despite its potential to increase NAE [net acid excretion]) also significantly improves the capacity for renal net acid excretion by stimulating urinary ammonium excretion. CONCLUSION: An adequate concept to estimate renal NAE and potential renal acid loads from dietary intakes must consider the specific bioavailability of the individual nutrients. Furthermore, an increased protein intake does not necessarily result in an accordingly increased use of endogenous acid excretion capacity for two reasons: 1) additional alkali loads in an appropriately composed diet can compensate for the protein-related raised acid production and 2) protein itself moderately improves the renal capacity to excrete net acid by increasing the endogenous supply of ammonia which is the major urinary hydrogen ion acceptor.PMID: 11842946 [PubMed - in process] See also: [3] Eur J Nutr 2001 Oct;40(5):189-99 History of nutrition and acid-base physiology.Manz F.Research Institute of Child Nutrition, Dortmund, Germany. manz@... PMID: 11842944 [PubMed - in process] [4] Semin Dial 2000 Jul-Aug;13(4):221-6 Influence of diet on acid-base balance.Remer T.Research Institute of Child Nutrition, Dortmund, Germany. remer@... PMID: 10923348 [PubMed - indexed for MEDLINE] [5] Am J Clin Nutr 2000 Jan;71(1):142-51 Dietary influences on bone mass and bone metabolism: further evidence of a positive link between fruit and vegetable consumption and bone health? New SA, Robins SP, MK, JC, Garton MJ, Bolton- C, Grubb DA, Lee SJ, Reid DM.Centre for Nutrition and Food Safety, School of Biological Sciences, University of Surrey, Guildford, United Kingdom. s.new@...CONCLUSION: The BMD results confirm our previous work (but at peripheral bone mass sites), and our findings associating bone resorption with dietary factors provide further evidence of a positive link between fruit and vegetable consumption and bone health.PMID: 10617959 [PubMed - indexed for MEDLINE] [6] Am J Clin Nutr 1999 Apr;69(4):727-36 Potassium, magnesium, and fruit and vegetable intakes are associated with greater bone mineral density in elderly men and women.Tucker KL, Hannan MT, Chen H, Cupples LA, PW, Kiel DP.Mayer US Department of Agriculture Human Nutrition Research Center on Aging at Tufts University, Boston, MA 02111, USA. tucker@...CONCLUSION: These results support the hypothesis that alkaline-producing dietary components, specifically, potassium, magnesium, and fruit and vegetables, contribute to maintenance of BMD.PMID: 10197575 [PubMed - indexed for MEDLINE] The Full Text concludes: "…Although the evidence remains limited, our findings support the hypothesis put forth by Wachman and Bernstein (14) in 1968 that a diet emphasizing the "ingestion of fruits, vegetables, vegetable protein, and moderate amounts of milk," all good sources of potassium and magnesium, may be protective of bone. Further investigation of the suggestion that these nutrients serve to buffer the acid load of the diet and thereby reduce bone loss is warranted." http://www.ajcn.org/cgi/content/full/69/4/727 [7] Osteoporos Int 2001;12(6):493-9 Diet acids and alkalis influence calcium retention in bone.Buclin T, Cosma M, Appenzeller M, Jacquet AF, Decosterd LA, Biollaz J, Burckhardt P.Division of Clinical Pharmacology, University Hospital (CHUV), Lausanne, Switzerland. thierry.buclin@...The urine-acidifying properties of food constituents depend on their content of non-oxidizable acids or precursors. Acidifying constituents such as animal proteins may negatively affect calcium metabolism and accelerate bone resorption, thus representing an aggravating factor for osteoporosis. This four-period, double-crossover study investigated whether a diet intervention specifically focused on acid load could modify calcium metabolism in humans.... This observation confirms that renally excreted acids derived from food influence calcium metabolism, and that alkalizing nutrients inhibit bone resorption. Further studies are needed to determine the clinical impact of dietary counseling for avoiding diet acids as a preventive measure against osteoporosis.PMID: 11446566 [PubMed - indexed for MEDLINE]