Vitamin C: Good for Your Bones

Sept. 19, 2008 -- A high intake of vitamin C may help reduce bone loss, at least in elderly men, according to a new study.

"Vitamin C had an effect on the [bone density of] hips in men, but it didn't have an effect on women," says Katherine L. Tucker, PhD, a senior scientist at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University and senior author of the study. It is published in the Journal of Nutrition.

Vitamin C and Bones: Background

For years, researchers have known that vitamin C is needed for normal bone development and for the formation of collagen, the fibrous protein part of bone, cartilage, and other structures.

But few studies have looked at the relationship between vitamin C intake from food and supplements and bone density, Tucker says.

Vitamin C is an antioxidant vitamin and reduces oxidative stress, which has a negative effect on all cells in the body, she says. "Antioxidants are needed to protect against oxidative stress, therefore protecting against inflammation. Inflammation drives bone resorption, which is basically taking calcium away from the bones. Vitamin C, theoretically, should help slow that resorption."

Vitamin C and Bones: Study Detail

Tucker and her colleagues evaluated the bone density of 213 men and 393 women, average age 75 at the start, over a four-year period to see what association their vitamin C intake had with their bones.

The participants were part of the long-running Framingham Osteoporosis study. The researchers looked at a diet questionnaire given to participants in 1988 or 1989 and again four years later. They evaluated the change in bone density in the hips, spine, and arm over the follow-up. Besides looking at their vitamin C and vitamin E intake, they took into account whether participants smoked and whether the women were on hormone replacement therapy.

Vitamin C and Bones: Study Results

Men with the highest vitamin C intake had the least bone loss in the hip. A similar finding in women was not significant, Tucker says.

The effect became most significant, she says, at the highest level, about 314 milligrams of vitamin C daily from supplements and food. The recommended intake is 75 milligrams daily for women and 90 milligrams daily for men.

"At one hip site [of two measured], for example, men in the highest intake group, who took in 314 milligrams of vitamin C a day in food and supplements but had low calcium intake, did not lose bone density on average," she says, ''whereas those in the lowest group, who took in 106 milligrams, lost 5.6% of their bone."

"The only significant effects on bone loss were found in men who were low in vitamin E or calcium," she says.

Why no effect was not seen in women is complicated, Tucker says. The effects of vitamin C may interact with estrogen use, calcium, and vitamin E, she notes.

Vitamin C and Bones: Second Opinion

The new finding is "interesting and plausible," says Robert P. Heaney, MD, professor at John A. Creighton University in Omaha and a longtime researcher in osteoporosis.

"There is good biology behind it," he says. "If you don't have enough vitamin C, you don't make bones right. Collagen is the principal protein of bones, accounting for nearly half the volume. What the collagen does is prevent bones from coming apart."

In recent years, says Heaney, researchers have found that maintaining bone density requires not just getting enough calcium, but also vitamin D and protein. Now, more evidence is emerging about the important role of vitamin C and bones as well, he says.

Vitamin C and Bones: Advice

The new research isn't a call to dose up with supplements, Tucker says. She believes in getting as much vitamin C as possible from fruits and vegetables, supplementing with a vitamin tablet if necessary.

Getting enough vitamin D and calcium is also still important for bone maintenance, she says.

Heaney agrees and adds this advice: "Eat a good diet. Exercise, walk, skip rope, jog.''

Thursday, September 25, 2008

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Thinking with Maynard Clark - Being Together IS Thinking

A RADICAL push has been staged within the RSPCA to endorse vegan diets as the best way to prevent cruelty to farmed animals.

A motion to the taxpayer-assisted body's annual general meeting on Wednesday called for it to adopt a range of controversial policies, including:

RECOGNISING egg, milk and chicken, pig and rabbit meat production "inflicts high levels of physical and psychological suffering on tens of millions of animals each year".

ACKNOWLEDGING a vegetarian or vegan diet was "the most effective way to significantly reduce cruelty to animals farmed for meat, eggs and milk".

ASKING RSPCA members to consider changing to a vegetarian or vegan diet.

Vegan diets exclude any animal product, including dairy food.

The motion was put by a "reformer" – one of a group within the RSCPA that aims to make the organisation more proactive on animal rights.

However, critics within the RSPCA have slammed the policy push as "pie in the sky" and out of touch with community values. While the motion was defeated, one of the reformers, Rosalie McDonald, was voted on to the RSPCA board and will stand for president in the ballot next week.

Ms McDonald said the motion was defeated only because it was presented at the end of a long meeting and "about half the members had left by then".

"I voted for it because there is nothing wrong with it," Ms McDonald, 67, said.

"They say a high fibre diet is much better for you."

Ms McDonald, a semi-retired businesswoman who said she was not personally a vegetarian, described herself as a "reformer".

"I feel the RSPCA management or president may represent us as . . . lunatics but with my particular background I hope they all realise I'm not a nutter," the former teacher and local government councillor said.

The "reformer" who proposed the motion, former Animal Liberation president Peter Adamson, admitted he was branded a "food Nazi" at the meeting. But he defended the push and said the general public should consider vegetarian diets to reduce animal cruelty.

"It would be very educational for the RSPCA to encourage its members to be vegetarians and this is something I would like the general public to consider," the former teacher, 62, said.

Ms McDonald said she wanted to become president to "reform the RSPCA to do what it is supposed to do".

"It's supposed to get out to the public arena and advocate the abolition of cruel practices . . . factory farming, battery hens and pork production."

Ms McDonald also wants to increase RSPCA membership and funding.

But RSPCA member and veterinarian Andrew Carter said resolutions like the one supported by Ms McDonald "would put off middle-of-the-road people and have a negative impact on membership".

"The message from that resolution is the RSPCA is trying to tell people what to do . . . but I don't think becoming a vegetarian will solve problems of animal cruelty," Dr Carter, who joined the RSPCA a year ago to represent mainstream values, said.

The motion was also attacked by former RSPCA national president Hugh Wirth who said the issue of animal food production and animal cruelty "won't be resolved by a few people changing their dietary habits" and to think so was "pie-in-the-sky" thinking.