Health Matters
From "Maple Street Co-op News", December 2007/January 2008

Milking the Calcium Myth By Kathryn Alexander, DThD

It may surprise you to learn that there is no scientific evidence to support any assertions that increased dietary or supplemental calcium builds strong bones. Following decades of propaganda by the dairy industry and medical fraternity on the value of calcium, the results of studies undertaken since the 1980s have failed to support this hypothesis. With the prevalence of osteoporosis and low bone mass escalating, where 10 million Americans currently suffer with osteoporosis and a further 34 million have low bone mass (these figures represent 55 per cent of the 50-plus age group)1 and with the health bill for related fractures now exceeding US $18 billion per annum,2 research is now focusing on the real factors that determine bone density.

The calcium myth exposed
We have long known that indigenous communities in India, Japan and Peru, have a very low incidence of bone fracture on an average daily calcium intake of less than 300 mg/day. Indeed, the incidence of bone fracture in black South Africans, with a daily calcium intake of 192 mg, was 10 times less than reported in African-Americans and 17 times less than white Americans.3 To date, various studies that have tried to prove the hypothesis that increased dietary calcium intake has a positive effect on bone health have failed. In 1980 a prospective 12-year study involving 77,761 women examined whether higher intakes of dietary calcium during adult years would reduce the risk of osteoporotic fractures. The study found no evidence that a higher intake of dietary calcium reduced fracture incidence and furthermore, went on to state that the "data [did] not support the hypothesis that higher consumption of milk or other food sources of calcium by adult women protects against hip or forearm fractures."4

In 1990, 81 prepubescent girls (average age 11.9 years) were tracked for six years. As teenagers gain 40-60 per cent of their skeletal mass during adolescence (and this underpins bone health in later life), it is easier to assess key influences on bone health during this period. The researchers found that none of the girls with low calcium intake (500 mg/day) showed any difference in bone development from those with high intake (1,500 mg/day). What the authors did find, was that exercise was a primary determinant in bone mineral density and that peak hip mineral density was determined by daily exercise such as walking rather than intense bursts of exercise.5

Focus on vitamins D and K
We can now be confident that poor bone density is not due to a primary calcium deficiency, however it can be caused by a secondary calcium deficiency - that is, factors that impair its absorption, increase its losses via the kidney or inhibit mineralisation of bone.

The role of vitamin D immediately springs to mind. Vitamin D is not only essential for the absorption of dietary calcium, but also stimulates the bone-building cells (osteoblasts) to produce osteocalcin, a protein that binds calcium. The best source of vitamin D is from sunshine. The action of the sun on the skin converts cholesterol to vitamin D, which is then rapidly absorbed. The kidneys convert it to its active form, calcitriol, which stimulates the production of a calcium-binding protein required for the uptake and transport of dietary calcium across the gut. It doesn't matter how much calcium you take, without adequate vitamin D it will not be absorbed. So how much do we need? Studies have found that at least 800 IUs (International Units) are required daily to reduce the risk of fracture. It is very difficult to get this amount through dietary sources - you would have to drink at least eight glasses of milk or eat 250 grams of salmon to achieve this. However, in a light-skinned person, a 30-minute, full body exposure to summer sun at noon triggers the release of about 20,000 IU of vitamin D into the circulation; in a dark-skinned person, this would create about half as much vitamin D. I am not suggesting that we all strip off at noon, but you can see that a reasonable exposure of a small area of skin to the sun each day would be sufficient to generate enough vitamin D. It is easy to see why people living in tropical climates can utilise their dietary calcium intake more effectively than those living at latitudes above 40-degrees, who are dependent on stored vitamin D during the winter months.

Once the calcium is absorbed, its binding to osteocalcin in the bone is dependent upon vitamin K (RDA 90-120 micrograms [mcg]) which is found in green leafy vegetables. The Nurses' Health Study (1980) followed more than 72,000 women for 10 years. Data indicated that the bone-protecting effect of vitamin K was greater than synthetic oestrogen in post-menopausal women and that nurses who got the most vitamin K were a third less likely to get a hip fracture - indeed women who ate lettuce daily slashed their risk of hip fracture by 50 per cent compared to those who ate it once a week or less.6 All green vegetables are good sources of vitamin K, but one cup of cooked broccoli will give you 420 mcg of vitamin K.

Acid/alkaline connection
However, getting enough calcium and vitamin D isn't enough. There are many studies from Harvard, Yale7 and San Francisco8,9 universities that indicate that diets high animal protein and low in fruit and vegetables increase renal (kidney) excretion of calcium and the bone marker, C-telopeptide (NTX) (indicating a skeletal origin for the excess calcium output), correlating to a significant increase in rate of hip fracture. Protein derived from vegetable sources exerted none of these negative effects. So it doesn't appear to be the amount of protein you have, but the type.

¥ Net acid excretion: A by-product of animal protein digestion is sulphuric acid, an acid ash. The kidneys are responsible for eliminating acids, but there is a limit to the speed at which they can do this and their concentrating capacity. Therefore, we have an efficient buffering system within the body - the bones. A slight drop in pH (more acid) stimulates osteoclasts (bone dissolving cells) to digest bone protein and release bound calcium in exchange for the acidity. To underline this, the Nurses' Health Study showed that women who had five or more serves of red meat per week had a significantly increased risk of forearm fracture compared to less than one meal per week.10

However, if you eat foods that leave an alkaline ash, such as your fruits and vegetables, or if you exchange animal protein for vegetable protein (beans, rice), which comes with their own buffers (can neutralise their own acidity), the bones are spared. In 1997 Appel et al.11 showed that by increasing fruit and vegetables from 3.6-9.5 serves daily, calcium excretion decreased from 157 mg/day to 110 mg/day.

This has major ramifications. A chronic net acid loading over many years will slowly dissolve the bones. A daily negative calcium balance of 50 mg over 20 years amounts to a total loss of 365 g, equivalent to half the bone calcium in females and one-third bone calcium in males. Furthermore, in the elderly the kidneys have a reduced capacity to eliminate acids. Consequently, their blood pH tends to be more acidic resulting in greater renal calcium losses and accelerated bone loss.

¥ Sodium chloride: Sodium chloride is an acid salt. UCSF (University of California, San Francisco) undertook a study to determine the effects of a high salt diet (9 g) on calcium excretion and bone loss. They found that a positive calcium balance was maintained on the low salt diet (2 g/day), but on the high salt diet (9 g/day) calcium and NTX excretion increased 33 and 23 per cent, respectively. However, adding 3.5 grams of potassium bicarbonate, an alkaline salt (an amount equivalent to eating 10 bananas) to the high salt diet, reversed the results leading to a positive calcium balance. The alkaline salt neutralised the effects of the high sodium acidic load.12 (Sodium bicarbonate, although an alkaline salt, does not match the effects of potassium salts.) Imagine what the results may have been on a low salt, high potassium diet!

¥ Cola drinks: Soft drinks that are high in phosphoric acid will also leach calcium and reduce bone density. Coca Cola has a pH 3.0. This means that if you drink 330 mls you would need to produce 33 litres of urine to remove the acidity via the kidneys. Obviously you can't do this; so the bones will buffer the acidity. All women are at risk from the effects of cola drinks, especially teenagers, who are laying down their bone calcium, and post-menopausal women.13

My advice:
• Think twice about going on high protein/low carbohydrate or ketogenic diets
• Reduce your amount of animal protein and counter-balance with quantities of fruits and vegetables
• Reduce your salt intake
• Reduce your caffeine and alcohol intake
• Ensure plenty of magnesium-rich foods (legumes, grains, nuts - magnesium is required for vitamin D activity)
• Make sure you eat greens (for vitamin K)
• Expose yourself to sunshine daily; and
• Exercise daily to stimulate the bone-forming cells.

If you follow the recommendations in my book Dietary Healing: the complete detox program (available from the Co-op or my website) you won't go wrong!

Endnotes
1. 'Prevalence and incidence of osteoporosis' http://www.wrongdiagnosis.com/o/osteoporosis/prevalence.htm
2. National Osteoporosis Foundation http://www.nof.org/osteoporosis/diseasefacts.htm
3. 'Sorting through the calcium myths'; http://www.vegsource.com/articles/calcium_update.htm
4. Feskanich, D. et al. 'Milk, dietary calcium, and bone fractures in women: a 12-year prospective study'. Am J Public Health; 1997; 87:992-7
5. Lloyd, T. et al. 'Adult female hip bone density reflects teenage sports-exercise patterns but not teenage calcium intake; PEDIATRICS Vol. 106 No. 1 July 2000, pp. 40-44 http://www.pediatrics.aappublications.org/cgi/content/full/106/1/40
6. Mitchell, T., Vitamin K; LE magazine; Feb 2000 http://www.lef.org/magazine/mag2000/feb00-report.html
7. Abelow BJ, et al. 'Cross-cultural association between dietary animal protein and hip fracture: a hypothesis'. Calcif Tissue Int; 1992;50 (1):14-18. http://www.springerlink.com/content/35211uv240638198/
8. Sellmeyer, D. et al. 'A high ratio of dietary animal to vegetable protein increases the rate of bone loss and the risk of fracture in post-menopausal women'. Am J Clin Nutr 2001 Jan;73(1):118-22
9. 'High Animal Protein Intake May Increase Risk Of Bone Loss And Fractures In Elderly Women, UCSF Study Finds' Science Daily; Dec. 28, 2000 http://www.sciencedaily.com/releases/2000/12/001227082125.htm
10. Feskanich, D. et al. 'Protein consumption and bone fractures in women'. Am J Epidemiol 1996 Mar 1;143(5):472-9.
11. Barzel, U. S. et al. 'Excess Dietary Protein Can Adversely Affect Bone' J Nutr Vol. 128 No. 6 June 1998, pp. 1051-1053 http://www.jn.nutrition.org/cgi/content/full/128/6/1051
12. Harris, E. 'Potassium-rich foods can help offset high salt diet contribution to osteoporosis' UCSF study finds UCSF News Office 23 May 2002 http://www.pub.ucsf.edu/newsservices/releases/200307221
13. Tucker, K et al. 'Colas, but not other carbonated beverages, are associated with low bone mineral density in older women: The Framingham Osteoporosis Study' http://www.ajcn.org/cgi/content/abstract/84/4/936

[Kathryn Alexander has written extensively on health issues, drawing on her training, her 20 years as a practitioner in detoxification and her expertise from nutritional healing research. Kathryn has a clinic in Maleny, offering a wide range of services from advice on treating simple ailments through to developing a suitable long-term plan for a chronic disease.

To make an appointment, email kathryn@getalife.net.au
or call (07) 5435 8138 during office hours.]

[From "Maple Street Co-op News", December 2007/January 2008; published by The Maple Street Co-operative Society Ltd, 37 Maple Street, Maleny, Qld 4552, Australia, tel (07) 5494 2088, email maplest.coop@serv.net.au,
website http://www.maplestreetco-op.com.au]