2007-06-10 - Calcium and Dietary Acid-base Balance in PWS

I wrote the following when someone on the HolisticPWS list asked about calcium intake for those PWS because osteoporosis is such a serious issue for many with PWS.

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> what is your opinion on how much calcium
> individuals with PWS should be getting?

I think it depends in good part on what their diet is like, that is, whether it tends to be acid- or alkaline-forming. The focus in osteoporosis prevention these days is on calcium intake, but an equally important question is what happens to the ingested calcium - is it used for building and maintaining bone, or is it used for maintaining the body's acid-base balance, that is, the body's critical need to keep its pH within a fairly narrow range (for example, blood is normally slightly basic (alkaline), with a pH range of 7.35 to 7.45) because even minor deviations from normal pH can cause serious havoc with cell permeability and function, severely impair many organs. pH chemistry, how the body maintains proper acid-base balance, and how all that ties into calcium metabolism are fairly involved topics, so the following is somewhat simplified.

There are two basic ways that the body's acid-base balance can get thrown out of whack - it can become too acidic (which is known as acidosis) or too alkaline (referred to alkalosis). Acidosis is the more common medical problem and is the acid-base problem that is most likely to occur in PWS. Acidosis is also a major contributor to the urinary loss of calcium, so I will be focusing on acidosis here.

There are two main ways in which acidosis develops. One has to do with respiratory problems (respiratory acidosis), for example, hypoventilation (which is common in PWS) results in a buildup of carbon dioxide (CO2), which then combines with water to form carbonic acid. The other main cause of acidosis is metabolic issues (metabolic acidosis) such as mitochondrial dysfunction (also probably common in PWS). Diet also has a significant impact on the body's metabolic acid-base balance. Meats, fish, eggs, grains, legumes, dairy products (especially cheeses) and salt are all acid-forming foods, that is, their metabolization results in the production of acid-forming hydrogen ions (H+). Fruits and vegetables, on the other hand, are almost all alkaline-producing (there is a chart below my signature with the acid-base values for some common foods). The typical modern diet, with its large amounts of acid-forming grains, dairy products, legumes and salt (which often take the place of alkaline-forming vegetables and fruits), can therefore lead to a chronic tendency to acidosis. The following chart illustrates just how unbalanced a supposedly "balanced" diet actually is in terms of acid-base balance when compared to the foods available for human consumption prior to the adoption of agriculture 10,000 years ago, that is, during most of the 2.5 million years of human evolution:

As you can see, the modern diet is badly skewed toward acid-forming foods. That's bad news because when the body's acid-base balance starts tilting towards acidosis, it must draw on its base/alkaline stores - the largest source of which is the calcium in bones - to buffer the acidity. The end result is the urinary loss of calcium, so it's not surprising that although the U.S. has one of the highest rates of calcium intake in the world, it also has one of the highest rates of osteoporosis.

Based on the lab test results for those with PWS that I've reviewed, as well as the respiratory weakness and mitochondrial impairment that are common in PWS, I believe that most of those with PWS have a marked tendency toward acidosis, a situation that will only be exacerbated by a diet composed primarily of acid-forming foods. Even leaving aside other reasons for poor bone mineralization in PWS, such as the low GH that is fairly common in PWS, it is therefore no surprise that osteoporosis is a serious problem in PWS. Given the role of grains, dairy products, legumes and salt in the urinary loss of calcium, I would therefore strongly suggest their removal from the diet or at least a sharp restriction of them for those with PWS. If that is done and care is taken that good amounts of calcium-rich veggies are included (see chart below), a multi-mineral supplement that contains around 50% of the age-appropriate RDA for calcium (see chart below) would probably still be a good idea for those with PWS in order to ensure that there is enough calcium to also buffer any excess acid formation that might be caused by respiratory weakness and mitochondrial impairment. If one opts to continue to include grains, dairy products, legumes and salt in the diet, then a supplement that contains at least 100% of the RDA would probably be advisable. (As with all nutritional supplements, mineral supplements should be taken in at least two divided doses in order to maximize uptake.)

For those that are concerned that the elimination of dairy products will result in insufficient calcium intake, I will note that the human species did quite well during the vast majority of its roughly 2.5 million years of evolution without access to dairy products (or calcium supplements, for that matter :). Indeed, the archaeological record indicates that around the world, human height actually decreased around 6 inches due to poor nutritional status whenever agriculture (that is, grains) was introduced. Similarly, studies have repeatedly found that hunter-gatherers typically have excellent bone mineral density even into old age and that osteoporosis only appears when the shift to agriculture is made and grains, legumes, dairy products and salt become dietary staples.

So how did humans manage to have such good bone health without milk and calcium supplements for all of those millions of years? There are several parts to the answer. One obvious factor is that their diet of animal protein, non-starchy vegetables, fruits and nuts helped keep their acid-base balance within optimal range so their calcium intake wasn't being used to buffer the excess acidity created by a diet skewed towards acid-forming foods. It should also be noted that grains and legumes such as soy contain phytates that bind with calcium, zinc and other important minerals, thereby significantly impairing their absorption. In addition, many leafy green vegetables and nuts are excellent sources of calcium (see chart below), so pre-agricultural calcium intake generally was equal to today's milk-mustachioed children and adults. Our hunter-gatherer forebearers were also active (i.e., not sitting in front of a computer writing long emails :-) and weight-bearing exercise is well-known to promote strong bones. Finally, they were also out in the sun a lot, which allowed their skin to form plenty of the vitamin D that is essential for healthy bone development.