New findings from the Iowa Women’s Health Study suggest that supplement use in post-menopausal women is linked to increased mortality. Jack blogged about this research yesterday, and I want to also mention it here since I’ve had quite a few questions about it.
As Jack noted, the research on supplements and mortality is very conflicting and it would be a mistake to draw firm conclusions from this study alone. Some of the findings are not supported by other research. That doesn’t make them wrong—it just means that they are not the final word on the subject. This is also an epidemiological study, and while it’s a very good and highly respected one, it still doesn’t provide evidence about cause and effect.
Finally, this study looked at types of supplements taken, but didn’t provide much information on amounts. The findings do suggest that taking huge doses of iron may be harmful. For people who have iron-deficiency anemia, big doses can be necessary, but they should always be taken under a doctor’s supervision and for only as long as needed to reverse the deficiency.
Some may want to use this study to suggest that vegans shouldn’t take supplements. It’s tempting to believe that a diet based on a variety of whole plant foods plus an occasional B12 supplement will automatically meet all nutrient needs.
But vegan diets always need to be supplemented with B12 on a regular basis (not “occasionally”) and often with vitamin D. If you don’t use iodized salt you should take a supplement of iodine. I recommend a DHA supplement as well, although the research on benefits remain conflicting.
If your diet falls short on other nutrients, like calcium, iron or zinc, you can almost always tweak your food choices and cooking style to bring levels back up; supplements shouldn’t be necessary for these nutrients for most vegans, but for some, they may help. It can be difficult for women on low-calorie diets to meet needs for all nutrients; it’s also a challenge for vegans who shun higher-fat foods like nuts and seeds.
The research suggests that there are few benefits to taking supplements for those who are already meeting nutrient needs. But, there is no reason to think that using low dose supplements to make up shortfalls in nutrient intake is harmful.
@TheVeganRD I am wondering re DHA supplements. Isn’t it EPA thats adults need more of, while DHA is more important for kids? Thats what I heard anyway….Thank you.
DHA actually converts to EPA, although the consensus is that it’s good to have some of each in a supplement.But I don’t think either one is more important for any age group. There are still lots of questions about these compounds, though!
I always appreciate reading nutrition news from you and Jack and very much trust your advice; that includes taking others’ extreme interpretations of research studies with a big grain of salt. I’ve been reading a lot of comments over the last few days stating that supplements are purely bad and that vegans should get all their nutrients from a whole foods diet, etc. When deficiencies can be real concerns, as I have learned, these statements can feel so irresponsible. I take B12, vitamin D since I found out I’m deficient, and a multi, and I definitely feel like I’m making wise choices. Thank you for all you do.
Thanks so much, Erin. And I agree that you’re making wise choices.
[…] Link. Spread the word: […]
I was one of those taking B12 occassionally (which sometimes meant it went weeks between each dose). I thank you, Jack Norris and others who repeat the basic message of regular B12 intake. I take a separate B12 supplement twice a week. Costs almost nothing and done in a few seconds. I’ve marked my calendar to take it on the morning the same weekdays. By now it is a habit and I don’t think about it.
One of the reasons I take it every day is that I worry I’ll forget a twice-a-week regimen. Great idea to mark your calendar!
I also appreciate everything you post, it’s needed not just because some people aren’t informed, but because some people insist on spreading bad nutrition advice like…vegans don’t need a B-12 supplement.
Ginny,
What is your opinion of folic acid and cancer risk from supplements, particularly colon, lung and breast cancer? Is the weight of evidence in favor of a relationship or is it less certain?
Paul
I think it’s less certain. And there is evidence that folate deficiency is linked to a higher risk for certain cancers, too. But, this is also something that we vegans shouldn’t need to worry about. We tend to get enough folate, so most of us shouldn’t need to supplement with it. The only exception would be for pregnant women–and in that case, I think the benefits probably outweigh the risks.
“But vegan diets always need to be supplemented with B12 on a regular basis (not “occasionally”)”
Citation please.The dosage suggestions for vegans are guesstimates. That being said, any vegan who does not take regular doses of B12 is playing russian roulette with their health!
And I believe you are punting on the real question. Why is it that supplementation has been an abysmal failure when it comes to morbidity and mortality? What is it about whole foods that make them more protective than antioxidant supplements (especially since antioxidants kick ass in vitro)?
Yes, of course the B12 recommendations are guesstimates, as are many recommendations in nutrition. But there is no reason to think that someone could get enough B12 if the supplement once or twice a month. That’s the kind of “occasionally” I’m talking about.
I don’t necessarily expect supplementation to be beneficial in terms of mortality unless people are deficient. And the benefits of antioxidants overall are being questioned anyway!