December 04, 2008
Acid From Protein And Grains Increases Calcium Excretion

Bottom line: yet another reason to eat more fruits and vegetables.

Chevy Chase, MD—Diets that are high in protein and cereal grains produce an excess of acid in the body which may increase calcium excretion and weaken bones, according to a new study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM). The study found that increasing the alkali content of the diet, with a pill or through a diet rich in fruits and vegetables has the opposite effect and strengthens skeletal health.

"Heredity, diet, and other lifestyle factors contribute to the problem of bone loss and fractures," said Bess Dawson-Hughes, M.D., of Tufts University in Boston, Mass. and lead author of the study. "When it comes to dietary concerns regarding bone health, calcium and vitamin D have received the most attention, but there is increasing evidence that the acid/base balance of the diet is also important."

Most people do not eat enough vegetables. Are you like most people? Or are you special?

Either eat your veggies or take potassium bicarbonate.

Average older adults consume diets that, when metabolized, add acid to the body, said Dr. Dawson-Hughes. With aging, we become less able to excrete the acid. One way the body may counteract the acid from our diets is through bone resorption, a process by which bones are broken down to release minerals such as calcium, phosphates, and alkaline (basic) salts into the blood. Unfortunately, increased bone resorption leads to declines in bone mass and increases in fracture risk.

"When fruits and vegetables are metabolized they add bicarbonate, an alkaline compound, to the body," said Dr. Dawson Hughes. "Our study found that bicarbonate had a favorable effect on bone resorption and calcium excretion. This suggests that increasing the alkali content of the diet may attenuate bone loss in healthy older adults."

In this study, 171 men and women aged 50 and older were randomized to receive placebo or doses of either: potassium bicarbonate, sodium bicarbonate, or potassium chloride for three months. Researchers found that subjects taking bicarbonate had significant reductions in calcium excretion, signaling a decrease in bone resorption.

"In this study, we demonstrated that adding alkali in pill form reduced bone resorption and reduced the losses of calcium in the urine over a three month period," said Dr. Dawson-Hughes. "This intervention warrants further investigation as a safe and well tolerated supplement to reduce bone loss and fracture risk in older men and women."

Do you want to become like those shrunken old women who are a half a foot shorter and visibly folding inward? Or will you eat more veggies and less grain and meat?

Share |      Randall Parker, 2008 December 04 01:01 AM  Aging Diet Bone Studies

Lou Pagnucco said at December 4, 2008 7:17 AM:

Besides causing calcium loss, a diet too high in meat and grains may contain an excessive amount of phosphorus, possibly causing vascular and soft tissue calcification - a reason why dialysis patients are put on low phosphosus diets.

I believe that bicarbonates are sometimes used by athletes (and illegaly fed to race horses) to increase endurance.

It may be possible that increasing dietary alkalinity might prevent muscle loss in the elderly - refer to:
"Potassium Bicarbonate Reduces Urinary Nitrogen Excretion in Postmenopausal Women"

Also, I recall reading that mild acidosis may promote plaque formation in Alheimers.

However, don't sodium/potassium bicarbonates pose risks for people kidney, and other medical problems?

Fat Man said at December 4, 2008 8:27 AM:

Be careful with that KHCO3, it is probably fairly toxic. NaHCO3 is much less toxic although it should be treated like an equal quantity of salt.

* said at December 4, 2008 11:49 AM:

I don't remember what a patient of mine was admitted for, but I'll always remember the phone call from lab: Patient's potassium is 6.9!

I still remember the feeling of panic and fear spreading through me as I flipped through the dr's rolodex. Either the dr was asleep, or about to doze off, but when I repeated that number, I can't repeat what the dr said in mixed company, but thankfully Kayexalate and EKG was the next thing the dr said.

Turns out the patient had been prescribed potassium chlorate a month or so earlier, and either someone forgot to tell the family to stop giving her the potassium once her bloodwork came back normal, or they didn't understand. Bottom line, they continued giving her potassium after her blood levels were normal.

Her EKG was fairly normal, and we managed to get her to finish the Kayexalate. Beyond that, I don't know, because sometimes we only see them for a single shift.

I think I'd rather drink lemonade sweetened with stevia, or eat watermelon to alkalize myself than play Russian roulette with potassium.

tom bri said at December 6, 2008 3:24 AM:

Still a point of scientific contention whether animal protein causes loss of calcium or weak bones. Check out the link below for one showing a positive correlation. Plenty more out there that show the same.

Randall Parker said at December 7, 2008 12:57 PM:

tom bri,

I read that abstract. Surprising. In that study vegetable protein has a negative correlation with bone mineral density (BMD) while animal protein has a positive correlation. I wonder why.

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