Vitamin D Takes A Hit

Faithful readers of this blog (May 18 and August 29) have read my railings against Vitamin D for some time now. It never made sense to me that so many Americans were deemed to be Vitamin D deficient nor did it make much sense that as people got heavier that their blood test for Vitamin D would report lower levels although they wouldn't develop any deficiency symptoms. I even raised the question if it was possible that fat stored Vitamin D (fat soluble) is available to the body when needed.  While this question remains unanswered, the question of what defines a Vitamin D deficiency just got a new answer and I think it makes sense.

The Institute of Medicine (IOM) just revised the guidelines for what defines a Vitamin D deficiency.

First, a little about the IOM.  The Institute of Medicine (IOM) is an independent, nonprofit organization that

works outside of government to provide unbiased and authoritative advice to decision makers and the public. 

Established in 1970, the IOM is the health arm of the National Academy of Sciences, which was chartered under President Abraham Lincoln in 1863. Nearly 150 years later, the National Academy of Sciences has expanded into what is collectively known as the National Academies, which comprises the National Academy of Sciences, the National Academy of Engineering, the National Research Council, and the IOM.

Under the new IOM guidelines, you are considered to have adequate Vitamin D levels if your level is above 20 ng/mL. The previous level was 30 ng/mL. In one fell swoop, the IOM has essentially removed almost all Americans from the category of being Vitamin D deficient. 

You will no doubt hear push-back from those quarters that make money peddling Vitamin D and related advice, but you should essentially ignore them. The IOM is trustworthy.

So if you didn't have enough reasons yet to push aside your multivitamins and Vitamin D supplements, perhaps this one will do the trick for you.

For the umpteenth time, eat whole foods including a wide variety of vegetables, fruits, beans, nuts, seeds, whole grains and Wild Salmon and you will consume all the vitamins, minerals, antioxidants and all the other health promoting nutrients you need for a healthy mind and body. Get 15-30 minutes of sun each day (earlier or later in the day and avoid reddening) and Vitamin D is also well covered. (You also get it from Wild Salmon.)

The key to a healthy life is to eat healthy every day.

The Only Thing I Know For Sure Is That We Need To Keep Learning

About 30 years ago, I read an article about agriculture that had a profound impact on my thinking. The article was about soil erosion and basically stated that what had long been considered an incontrovertible truth about how to avoid soil erosion turned out to be the exact opposite. The idea that something held as an absolute truth could prove to be absolutely wrong has given me pause to think about such 'truths' to this day.

Thirty years later, a new study about exercise emerges that reminds me of what we consider absolute truths may not be so. For as long as I can remember, exercise has been associated with increasing your metabolism. It's been widely believed that exercise contributes to weight loss by burning calories and increasing your metabolism, which is believed to keep revving and burning calories even during the cool down phase.  While certain people argued that exercise was not an effective way to lose weight because they were unsuccessful losing weight despite much exercise, it was still a tenet of the weight loss movement. For example, Weight Watchers allows you to add extra "points" based on the amount of exercise you do.

The new study, which is a wonderful study, titled Hunter-Gatherer Energetics and Human Obesity, (http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0040503) studied the Hadza tribe of hunter-gatherers in Tanzania. Strapping members of the tribe with a GPS device and having them swallow so-called doubly labeled water, a liquid in which the normal hydrogen and oxygen molecules have been replaced with versions containing tracers, researchers were able to quantify their levels of physical activity, energy expenditures and metabolic rates. What they discovered is groundbreaking!

The study showed that contrary to popular belief, exercise slows down one's metabolic rate so that calories burned are actually far less than expected.  What's amazing is that this is intuitive and yet for so long everyone believed otherwise. Think about it for a moment. If your body doesn't eat for several hours, we think (I'm now officially afraid to say anything for certain any more; well, maybe some things) your metabolic rate slows down as your body tries to conserve energy, as it doesn't know when energy will be replenished. Applying that same principle to exercise, when the body senses a loss of energy consumed by increased activity, it makes sense that it will slow down its burn rate to conserve energy.

This doesn't mean that you aren't burning calories and you can't lose weight by exercising. It simply means that you burn less than you think, which means don't think you can eat a lot more because you had a good exercise session.

By now you couch potatoes are turning to your spouses or friends and smugly telling them you were right all along about exercise. Well not so fast.  Exercise is still critical to good heart and brain health. Exercise keeps the heart functioning well and exercise has been shown to be as effective as anti-depressants in treating many cases of mild to moderate depression. But that's not all. Two new studies published online in the Archives of Internal Medicine support the tremendous impact of exercise on lowering the risk of death among diabetic patients, and that weight training may reduce the risk for the disease even without aerobic activity.

Quoting medpagetoday.com, "In a large prospective trial, moderately active patients with diabetes had a lower risk of total mortality compared with those who were completely inactive...according to Diewertje Sluik, MSc, of the German Institute of Human Nutrition in Potsdam, and colleagues. And in a separate prospective study, men who did weight training only at least 150 minutes per week had a 34% lower risk of developing diabetes to begin with ...according to Frank Hu, MD, PhD, of the Harvard School of Public Health in Boston, and colleagues."

I also previously wrote about a study that shows that exercise can return the inflexible blood vessels of pre-diabetics to normal as well.

So while exercise is not the great weight loss panacea it was once thought to be, it is still a critical component of a healthy lifestyle. Keep exercising, but more importantly, if you want to stay slim or lose weight avoid the four whites--white sugar, white flour, white pasta, and white rice. If you watched 60 Minutes this past Sunday, you now know that some scientists view sugar as toxic and cancer causing. Just another good reason to choose whole foods like fruits, vegetables, nuts, beans, and whole grains. And of course, don't forget my favorite, Wild Salmon.  Bon appetite!

A Hodgepodge of New Studies

Making Sense of Two Recent Testosterone Studies:

I am always trying to make sense of the studies I come across. In the past couple of days, I came across two studies involving testosterone, the male hormone. One study showed that overweight men who suffered from hypogonadism (a medical term which describes a diminished functional activity of the gonads, the testes in males) who received testosterone lost weight; the other study showed that men who suffered from hypogonadism who lost weight increased their testosterone to a level where they no longer had hypogonadism (incidence of hypogonadism went from 20% to 11%, about a 50% improvement).

After reading the two studies, I had to ponder for a while how they related to each other and then it came to me. Although I claim no absolute certainty in these conclusions, it seems that for certain overweight men, increasing testosterone, either endogenously (from within) or exogenously (from outside) helps them lose weight. Given the choice, it would seem better to naturally increase a hormone as opposed to getting it from some other derived source. The best way to do so if you are overweight is to change your diet to the a mostly plant-based diet, increase your exercise to moderately-intense 150 minutes per week, and get at least 7 hours of sleep a night.

Are Vitamin D Blood Tests Always Accurate?

Apparently not. A recent study showed that 40% of the time, blood-labs misdiagnose Vitamin D deficiency by reporting lower than actual levels. This may not be true for all labs or all types of equipment used. The equipment/tests that seemed to be the worst offenders were the Architect and Centaur-2 tests. The liquid chromatography/mass spectrometry (LC/MS) test is the gold standard and can generally be relied upon. So the next time you have a test, ask what equipment they are using and consider going to another lab with LC/MS equipment for greater peace of mind.


Is There A Link Between Vitamin B6 and Heart Disease?

A new study shows a link between low Vitamin B6 levels and increased risk for heart disease. The study does not show causality, which means it isn't clear if the low Vitamin6 causes the heart disease or the heart disease causes the low Vitamin B6. It is possible that the inflammation often seen in heart disease may decrease blood levels of the vitamin. Nevertheless, it is important to maintain adequate levels of all vitamins, including B6, so I include the reference table below for your edification.

This table is not meant to be a recommended diet; rather, it is meant to give you a representative sample of sources of Vitamin B6 in regularly available foods.  A healthy diet is one that contains fruits, vegetables, nuts, legumes (beans), whole grains, and fat from fatty fish like Wild Salmon and Wild Cod. It can also include some olive oil, limited red wine, and very occasional chicken or meat. This is often referred to as the Mediterranean Diet and it still seems to pack the most bang for the buck.
Food	Milligrams (mg) per serving	Percent DV*
Chickpeas, canned, 1 cup	1.1	55
Tuna, yellowfin, fresh, cooked, 3 ounces	0.9	45
Salmon, sockeye, cooked, 3 ounces	0.6	30
Chicken breast, roasted, 3 ounces	0.5	25
Breakfast cereals, fortified with 25% of the DV for vitamin B6	0.5	25
Potatoes, boiled, 1 cup	0.4	20
Turkey, meat only, roasted, 3 ounces	0.4	20
Banana, 1 medium	0.4	20
Marinara (spaghetti) sauce, ready to serve, 1 cup	0.4	20
Ground beef, patty, 85% lean, broiled, 3 ounces
Waffles, plain, ready to heat, toasted, 1 waffle	0.3	15
Bulgur, cooked, 1 cup	0.2	10
Cottage cheese, 1% low-fat, 1 cup	0.2	10
Squash, winter, baked, ½ cup	0.2	10
Rice, white, long-grain, enriched, cooked, 1 cup	0.1	5
Nuts, mixed, dry-roasted, 1 ounce	0.1	5
Raisins, seedless, ½ cup	0.1	5
Onions, chopped, ½ cup	0.1	5
Spinach, frozen, chopped, boiled, ½ cup	0.1	5
Tofu, raw, firm, prepared with calcium sulfate, ½ cup	0.1	5
Watermelon, raw, 1 cup	0.1	5

*DV = Daily Value. DVs were developed by the U.S. Food and Drug Administration (FDA) to help consumers compare the nutrient contents of products within the context of a total diet. The DV for vitamin B6 is 2 mg for adults and children age 4 and older. However, the FDA does not require food labels to list vitamin B6 content unless a food has been fortified with this nutrient. Foods providing 20% or more of the DV are considered to be high sources of a nutrient.

Calcium Pills Raise Concerns -- Again!

If you've heard me say it once, you probably have heard me say it many times -- taking dietary supplements in the absence of known deficiency is a mistake. One of the more controversial supplements I've rallied against has been calcium. Most women are told by their doctors, particularly as they get older, to take calcium supplements, usually about 1,000 mg.

When I give lectures, I often ask of the audience whose doctor adjusted their calcium recommendation based on the calcium the individual consumes through his or her food. The answer is almost always that none of their doctors made any such adjustment. I've always considered this problematic because why supplement at all if you are getting sufficient calcium in your diet, and why not adjust when you are getting calcium from other sources.

My real concerns about calcium began to grow almost two years ago when studies began to emerge challenging the wisdom of taking this supplement.  Specifically, these studies linked calcium supplementation with increased heart attack risks. Some studies suggested the mechanism for this, calcium supplements, were contributing to calcification, or hardening, of the heart.

So a new study that just came out should be of no surprise to my patients.

The large European study showed that people taking calcium supplements had nearly double the risk of heart attack as individuals not taking any dietary supplements. Among 23,980 participants in the European Prospective Investigation into Cancer and Nutrition (EPIC-Heidelberg) study, the hazard ratio for heart attack in those using calcium supplements, compared with nonusers of supplements, was increased according to Sabine Rohrmann, MD, of the University of Zurich in Switzerland, and colleagues.

"This study suggests that increasing dietary calcium intake from diet might not confer significant cardiovascular benefits, while calcium supplements, which might raise MI risk, should be taken with caution," the researchers concluded. In an accompanying editorial, two New Zealand physicians went further and suggested that use of calcium supplements should be actively discouraged.
 
This was an imperfect study as it was an observational study that relies on self-reporting. Nevertheless, once again, the red flag rises over taking calcium pills, or any dietary supplement for that matter. The evidence continues to mount that at best they confer no benefit, and at worst, they are harmful.

Eat a Mediterranean diet consisting of fruits, vegetables, beans, nuts, and some whole grains, add in some wild fish and save yourself some money from not buying unnecessary pills.