Low Micronutrient Intake may Contribute to Obesity

[2013 update: I'm skeptical of the idea that micronutrient insufficiency/deficiency promotes obesity.  Although the trial discussed below suggested it might be a factor, it has not been a general finding that micronutrient supplementation causes fat loss, and the result needs to be repeated to be believable in my opinion.  Also, conditions of frank micronutrient deficiency are not usually associated with fat gain]

Lower Micronutrient Status in the Obese

Investigators have noted repeatedly that obese people have a lower blood concentration of a number of nutrients, including vitamin A, vitamin D, vitamin K, several B vitamins, zinc and iron (1). Although there is evidence that some of these may influence fat mass in animals, the evidence for a cause-and-effect relationship in humans is generally slim. There is quite a bit of indirect evidence that vitamin D status influences the risk of obesity (2), although a large, well-controlled study found that high-dose vitamin D3 supplementation does not cause fat loss in overweight and obese volunteers over the course of a year (3). It may still have a preventive effect, or require a longer timescale, but that remains to be determined.

Hot off the Presses

A new study in the journal Obesity, by Y. Li and colleagues, showed that compared to a placebo, a low-dose multivitamin caused obese volunteers to lose 7 lb (3.2 kg) of fat mass in 6 months, mostly from the abdominal region (4). The supplement also reduced LDL by 27%, increased HDL by a whopping 40% and increased resting energy expenditure. Here's what the supplement contained:

Vitamin A(containing natural mixed b-carotene) 5000 IU
Vitamin D 400 IU
Vitamin E 30 IU
Thiamin 1.5 mg
Riboflavin 1.7 mg
Vitamin B6 2 mg
Vitamin C 60 mg
Vitamin B12 6 mcg
Vitamin K1 25 mcg
Biotin 30 mcg
Folic acid 400 mcg
Nicotinamide 20 mg
Pantothenic acid 10 mg
Calcium 162 mg
Phosphorus 125 mg
Chlorine 36.3 mg
Magnesium 100 mg
Iron 18 mg
Copper 2 mg
Zinc 15 mg
Manganese 2.5 mg
Iodine 150 mcg
Chromium 25 mcg
Molybdenum 25 mcg
Selenium 25 mcg
Nickel 5 mcg
Stannum 10 mcg
Silicon 10 mcg
Vanadium 10 mcg

Although the result needs to be repeated, if we take it at face value, it has some important implications:

• The nutrient density of a diet may influence obesity risk, as I speculated in my recent audio interview and related posts (5, 6, 7, 8, 9).
• Many nutrients act together to create health, and multiple insufficiencies may contribute to disease. This may be why single nutrient supplementation trials usually don't find much.
• Another possibility is that obesity can result from a number of different nutrient insufficiencies, and the cause is different in different people. This study may have seen a large effect because it corrected many different insufficiencies.
• This result, once again, kills the simplistic notion that body fat is determined exclusively by voluntary food consumption and exercise behaviors (sometimes called the "calories in, calories out" idea, or "gluttony and sloth"). In this case, a multivitamin was able to increase resting energy expenditure and cause fat loss without any voluntary changes in food intake or exercise, suggesting metabolic effects and a possible downward shift of the body fat "setpoint" due to improved nutrient status.

Practical Implications

Does this mean we should all take multivitamins to stay or become thin? No. There is no multivitamin that can match the completeness and balance of a nutrient-dense, whole food, omnivorous diet. Beef liver, leafy greens and sunlight are nature's vitamin pills. Avoiding refined foods instantly doubles the micronutrient content of the typical diet. Properly preparing whole grains by soaking and fermentation is equivalent to taking a multi-mineral along with conventionally prepared grains, as absorption of key minerals is increased by 50-300% (10). Or you can eat root vegetables instead of grains, and enjoy their naturally high mineral availability. Or both.