Vitamin D and the cardiovascular system

More evidence is out that vitamin D is important to the cardiovascular system and helps to prevent heart disease and strokes.

You can read more about vitamin D here. It's hard to get enough from food, and many parts of the country don't have enough sunshine, especially in the winter, for people to make enough on their own.

Get the right vitamin D

Since it's hard to get enough vitamin D through your diet (or through exposing your skin to sunlight, especially in the winter), a supplement is a good idea. Just make sure you are getting the right kind: vitamin D3 (cholecalciferol). Studies are finding that vitamin D2 doesn't seem to help the body as much, at least with respect to strengthening bones.

Vitamin D deficiencies in teenagers

A new study found a link between low vitamin D levels and a variety of health issues in teens:

Teens in the study with the lowest vitamin D levels were more than twice as likely to have high blood pressure and high blood sugar. They were also four times more likely to have metabolic syndrome, defined as have three of more conditions that contribute to heart disease and diabetes — including high blood pressure, high blood sugar, big waists and high cholesterol.

While 15 minutes of sunshine will allow your body to make what it needs in the summer, it's a lot harder to get enough that way in the winter.

The article went on to say:

The American Academy of Pediatrics recently doubled its recommended amount of vitamin D for children and teens to 400 units daily — the equivalent of drinking four cups of milk. The pediatricians group said kids who don’t get enough should take vitamin supplements.

The teen study looked at about 3,600 boys and girls ages 12 to 19 who took part in a government health survey from 2001 to 2004. The researchers used measurements of vitamin D from blood tests.

On average, none of the teens were getting enough vitamin D. Whites had the highest levels, blacks had the lowest levels and Mexican-Americans had levels in between.

More here.

Tanning beds, aging, & vitamin D

Tanning beds are pretty common even in a sunny place like Vegas, but apparently they outnumber McDonald's and Starbucks locations in some cities. And despite the warnings about the heightened risk of skin cancer from UV radiation, plenty of people still use them.

I spent a fair amount of time in tanning beds, especially back in the first half of the 90s when I was going on cruises almost every year. I wish I could have those hours back now, lol... I'm sure they did not help my skin. I wear SPF 45+ sunscreen when out in the summer sun these days. It's important to wear a broad spectrum UVA/UVB formula as I've read that UVA, long considered to be the "good rays," may actually be more likely to cause the type of damage that can lead to skin cancer. From a June 2007 article in NewScientist:

While sunburn is mostly caused by the part of the ultraviolet spectrum known as UVB, there's growing evidence linking melanomas to UVA. Older sunscreens allowed people to stay out in the sun longer without burning but provided little protection against UVA, so they increased people's exposure to these wavelengths.

If UVA really is responsible for melanoma, a whole generation may have been misled into thinking sunscreens allowed them to soak up the rays with impunity. Lawyers in the US have filed a class action lawsuit against a number of sunscreen makers alleging that labels such as "sunblock" are misleading, because the products do not "block" the whole UV spectrum and often imply equal UVA and UVB protection.

Unlike the people quoted in the tanning bed article, however, I'm still a believer that exposure to some natural sunlight each day is the best way to get enough vitamin D.

And if you've overindulged in the sun (or those pesky tanning beds), some early research suggests that skin peels of damaged tissue may head off skin cancers.

Vitamin update

A summary of the latest vitamin research. After taking a multivitamin since my teen years, I now only take a daily vitamin D supplement.

More on how much vitamin D is needed

I've written about vitamin D before, and I take a daily supplement (400 IUs in the summer, 1000 IUs in the winter).

Here is some more information which illustrates why many people may not be getting enough. A glass of fortified milk has 100 IUs, but a fair-skinned person in shorts and a tank top will produce 1000 IUs per minute in midday summer sun. Most Americans receive insufficient UV light in the winter to naturally produce any vitamin D.

Read more here.

Pediatricians say: more vitamin D for kids

The American Academy of Pediatrics has doubled its recommended daily dose of vitamin D for kids (from breastfeeding infants to teens). The new recommendation is 400 IU/day.

Kids are getting inadequate vitamin D to build bones strong enough to last a lifetime, and researchers continue to discover new ways in which the vitamin improves human health (e.g. strengthening the immune system).

More on vitamin D here.

Exercise notes

Several health-related stories caught my eye today, so before I start studying for tomorrow's anatomy & physiology exam, here they are.

THE NATIONAL OSTEOPOROSIS FOUNDATION released new guidelines today. They include:

• For adults over 50, 1,200 milligrams a day of calcium and 800 to 1,000 international units a day of Vitamin D, more D than the government recommends.
• Do regular weight-bearing and muscle-strengthening exercise. (More on this below.)
• Recommend that all men over 70 get bone-mineral density X-ray tests (just as already been recommended for women over 65). Earlier tests are recommended for those individuals with additional risk factors.
• Treat postmenopausal women and men 50 and older who have thinning bones, but not osteoporosis yet, if they have at least a 20 percent risk of any major fracture in the next decade, or at least a 3 percent risk of a hip fracture.
• Check for osteoporosis risk factors in postmenopausal women and men 50 and over, to see who needs a bone test before their senior years.
• A bone test for anyone who has any type of fracture after age 50, or who has conditions associated with bone loss, such as rheumatoid arthritis.

With regard to weight-bearing exercise as mentioned above, here's an article with some specifics on what does and doesn't help maintain bone mass. Both weight training and aerobics are helpful, though the latter has a caveat.

While aerobic activity of all kinds is good for general health, some forms don't help your bones. Those that don't include swimming, cycling, and... StairMasters and StairClimbers at the gym (I forced myself to get on the treadmill instead today).

Bone mass peaks in our 20s. After that it's a long slow decline... we can let it proceed at full speed or slow it with a combination of healthy food choices, adequate exposure to sunshine, and exercise (see the National Osteoporosis Foundation article mentioned above).

NEXT UP... FAT CELLS. When I was a freshman in college, I got the idea from my P.E. class that if I starved myself for six months, I could kill off some of my fat cells. I gave it a try with pretty bad results... during a regular check-up with my doctor, he thought I was become diabetic. He told me to start eating regularly again, and sure enough, I was soon back to normal.

In any case, the latest research indicates that once we enter our 20s, the number of fat cells in our body is pretty much set for the rest of our lives. While it may go up, it's not going to go down, even after weight-loss surgery.

So if you've got kids under 20, try to keep them from becoming overweight, and if they already are, work with your doctor to address the problem.

And if you're over 20 and overweight, what you can do is reduce the amount of fat stored in each fat cell. There's no magic formula: it's eat less and move more.

AND THAT'S GOOD ADVICE for most of us.

"New Jobs for Ancient Chaperones" in the July issue of Scientific American today examines the roles of so-called heat-shock proteins (HSPs) in the human body. Since they were originally discovered in an experiment that exposed flies to high temperatures, HSPs have been found in just about every living organism on earth. Their function is to keep essential cellular processes running, especially when the cell is exposed to stress. While heat was the original type of stress found to activate HSPs, researchers have since learned that other forms of stress do so as well: low oxygen conditions, cancer, infectious disease, etc.

There's some evidence that exercise puts just enough healthy stress on the body's cells--higher body temperatures, oxygen debt, and other metabolic changes--to engage the HSP mechanisms and boost our overall immune response.

So get moving. :-)

More on vitamin D

More research on the benefits of vitamin D:

New research linking low vitamin D levels with deaths from heart disease and other causes bolsters mounting evidence about the ''sunshine'' vitamin's role in good health.

Patients with the lowest blood levels of vitamin D were about two times more likely to die from any cause during the next eight years than those with the highest levels, the study found. The link with heart-related deaths was particularly strong in those with low vitamin D levels.

A couple of earlier posts on vitamin D here and here.

More on vitamin D

A few highlights from the articles about vitamin D that I mentioned this morning:

• Besides helping the body absorb calcium, vitamin D is an important immune system regulator with anti-inflammatory and anticancer actions. It plays a role in the activation of around 1000 different genes. New research is finding a link between increased risks of heart disease and diabetes in people who are deficient in the vitamin.
• There are few food sources, and the limited number of foods, like milk, that are fortified with vitamin D have fairly low levels of it.
• Vitamin D is produced by the body when the skin is exposed to UV light. Properly applied sunscreens, however, can reduce the body's ability to manufacture the vitamin by up to 98%. People living at higher latitudes are also hindered in their ability to make vitamin D by the lack of strong sunshine, especially in the winter.
• While the daily recommended allowance is 400 IUs, spending 15-20 minutes in midday summertime sun will naturally produce between 10,000 and 20,000 IUs. Spending more time does not produce higher levels of the vitamin as UV rays also degrade it.

Scientific American reports:

Accumulating evidence suggests that the subtle and longer-term effects of even slight vitamin D deficiency may be multifold and manifested later in life, in the form of increased frequency of bone fractures and enhanced susceptibility to infection and autoimmune diseases, as well as elevated frequencies of certain cancers. The research strongly implies that at the very least the general public would benefit substantially from greater awareness of the broad physiological benefits of vitamin D, a sound medical consensus on sensible sun exposure and a clear indication of optimal recommended daily intakes of vitamin D from dietary sources.

And from the LA Times:

Current guidelines call for blood levels of about 30 nanograms per milliliter. By that definition, perhaps 10% to 15% of white people in the U.S. and 50% of the black population is deficient in summer, with the percentages rising in winter when there is less sunlight.

Many researchers say that people should be striving for average blood levels of 50 to 60 nanograms per milliliter, at which level the bulk of the U.S. population would be considered deficient.

Most researchers in the field now take supplements of at least 1,500 IUs per day. Most recommend taking no more than 4,000 IUs because of potential toxicity.

Since reading the Scientific American article in January, I've started taking a 400 IU supplement (once daily in the summer, twice daily in the winter). Here in Vegas it's pretty easy to get 15 minutes of sun while I'm walking around campus.

UPDATE: Also see this post on a link between low vitamin D levels and an elevated risk of cardiovascular disease.

Sunshine and vitamin D

Recent research is once again underlining the fact that the Western lifestyle is undermining our health. By spending more time indoors--and slathering on the sunscreen when we're actually outdoors--it now looks like most Americans are deficient in vitamin D. While we may be getting enough to prevent rickets, the traditional reason cited for why we need the vitamin, we are likely not getting enough for vitamin D to perform its other, more recently discovered roles. Prime among these is its ability to help the immune system fight a myriad of diseases, including cancer and heart disease.

Scientific American featured an article in their January issue, "Cell Defenses and the Sunshine Vitamin," and the Los Angeles Times has an article today, "Sunshine may be nature's disease fighter."