Vitamin D: Bone Protection for Most

Vitamin D is essential to calcium absorption and functioning. So, without vitamin D it's impossible to gain optimal bone density or maintain it. “Children need vitamin D to build strong bones, and adults need it to keep their bones strong and healthy.”¹ Vitamin D helps to keep adult bones strong and dense well into middle-age and beyond. … If you're a man, that is. Vitamin D is not so useful for maintaining bone density and strength after menopause.

The age and gender factor

Research has shown that vitamin D fails to benefit bone health in women after menopause. According to the author of one study,

“While high-dose vitamin D did indeed increase calcium absorption, the increase was only 1 percent and [it] did not translate into gains in spine, hip or total body bone mineral density.”2 Dr. Karen Hansen, MD, MS, also noted that she and her colleagues “did not find any benefit of vitamin D, in either high or low dose, on muscle mass, two tests of muscle fitness or fall [risk].”²

Could artificial vitamin D be the problem?

Here's a quote from the study 'Treatment of Vitamin D Insufficiency in Postmenopausal Women: A Randomized Clinical Trial',

“High-dose cholecalciferol therapy increased calcium absorption, but the effect was small and did not translate into beneficial effects on bone mineral density, muscle function, muscle mass, or falls.”³

Cholecalciferol is an artificial form of vitamin D3. All vitamin D studies use artificial vitamin D – usually cholecalciferol because it's easier to control and track the dosages each study participant receives.

Vitamin D from the sun is manufactured in our skin, but our ability to manufacture vitamin D decreases with age. This is true for both men and women. It's the reason it was once recommended that everyone, but particularly women, take supplemental calcium after a certain age. This was before scientists recognized the importance of vitamin D for calcium absorption and utilization.

Subsequent research proved that calcium supplements could actually weaken bones. The participants in several studies experienced loss of calcium from their bones as a result of taking high doses of supplemental calcium. And even in studies where participants were given the RDA (recommended daily allowance) of calcium – 1,000 mg – there were no discernible bone benefits. This was also proven true for both men and women.

Here is a quote from one such study, with all male participants ranging from 30-87 years of age:

“Normal men experience a substantial bone loss at both axial and appendicular sites that is not prevented by calcium and vitamin D supplementation in a well-nourished population.”⁴

In this particular study, both the RDA of calcium and 25mcg (1,000 I.U.) of vitamin D, in the form of cholecalciferol, were given daily for 3 years. Yet, it has been proven in many other studies that, vitamin D supplementation alone can benefit the bones of older and elderly men.

Knowing this, it occurred to me that the loss of estrogen and, maybe, even progesterone could be the reason that postmenopausal women do not effectively absorb artificial vitamin D. Unfortunately, I couldn't find a single study that examined artificial vitamin D absorption as it related to estrogen therapy, or deficiency, in postmenopausal women.

However, I recently came across an old study that showed an increase in both vitamin D and calcium levels in the blood of postmenopausal women after undergoing (equine) estrogen therapy. You can read more about it in The Journal of Clinical Endocrinology and Metabolism.

Taking very high doses of Vitamin D is a bad idea... for women

There are also studies demonstrating that high doses of vitamin D (as much as 24,000 I.U./day in one study) lowered estrogen and progesterone levels in women and raised testosterone levels in men.

Researchers have yet to explain the reasons why vitamin D affects the reproductive hormones of men and women so differently. However, researchers at the University of California in Los Angeles did discuss how deficiencies in vitamin D and estrogen could be related to protein binding sites at the cellular level.

“Through complex scientific analysis, the paper reveals that there are specific proteins determined by DNA that control the ability of the body to use and process vitamin D and estrogen. This suggests that vitamin D resistant individuals may also be at risk for low levels of estrogen.”⁵

But, so far, there's no proof that the onset of menopause can interfere with protein binding sites in women. It's possible, but there's no evidence to back up that hypothesis because there's no research presently being done on this topic.

Preparing for the future

As it stands, all you can do nutritionally (if you're a woman) is eat, sunbathe and supplement for stronger denser bones, before you reach menopause, and hope that you've stored enough minerals to protect your bones well into old age.

If you're a man, you have less to worry about in terms of your ability to prevent bone loss as you age, because you will still be able to benefit from vitamin D supplements. If men fail to supplement as they grow old, they are putting themselves at unnecessary risk.

Men can and do develop osteoporosis. And the older a man gets, the greater his odds of developing the disease. 20% of all osteoporosis sufferers are men and, according to a study published in the BC Medical Journal, “Men represent between 20% and 40% of all patients with [fragility fractures].”⁶ Considering how detrimental to one's quality of life fractures can be in old age, everyone should do whatever they can to keep their bones dense and strong.

As I mentioned earlier, everyone manufactures less vitamin D from sunlight as they age and women don't benefit from supplemental vitamin D after menopause. So, what can postmenopausal women who didn't store enough bone mass do to keep their bones strong if they're not willing to take on the risks of estrogen therapy?

If you have any ideas or have found a natural, low-risk solution to that question, please share with us Mastodon or Facebook. I will research this topic further. Hopefully, there are feasible nutritional solutions for postmenopausal women out there.