Get in Mah Belly: Fun Size Food Facts
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Gluten-Free Diet
If food was fashion, Mugatu would most certainly agree, gluten is "so hot right now". Gluten-free diets have been proposed for a myraid of ailments - weight loss, depression, allergies, etc. It's even been proposed to be linked to autism. Heck even "Ms. Cyrus" is doing it? (citing celebrities, always smart) But is there any evidence for it? In short, no. Zilch.
Now I'm not talking about celiac disease/gluten-sensitive enteropathy. There's obviously plenty of data for it. That is a diagnosis that can be made with actual lab tests. However, gluten sensitivity is more of a catch-all phrase that has seen light more from pop culture than from medical literature. But that doesn't mean it's not real. Just that there is a lack of any evidence for it.
Reasons for not doing gluten-free diets? There are some but they aren't the greatest in the world in my opinion.
When you take out wheat, rye, and barley from your diet you tend to have less exposure to vitamins such as folate, B12, and iron as well as fiber. But let's be honest, the demographic that are going gluten-free are those that have better access to fruits and vegetables. I have yet to see an urban underserved patient at my clinic come asking about gluten-free diets. The person who has enough resources and is dedicated enough to go gluten-free is typically one who will supplement their diet with other healthy, non-gluten options.
B12 - fish, beef, yogurt
Folate - beans, spinach, lentils
Iron - beef, chicken, spinach, lentils
So for me? If a patient asked about a gluten-free diet, the most important question would be "why?" Once any other source of pathology was ruled out for their symptom, I would be fine trying a gluten-free diet on top of other more evidence-based treatments. In the end, the biggest hit won't typically be to your health, it'll be to your wallet.
Verdict: As long as you're otherwise healthy and supplementing your diet, I'm cool with it.
Multivitamins
When I think of multivitamins, I think of my mom. I can instantly flashback to high school when every morning there would be a pink multivitamin sitting in a small container just waiting for me downstairs. It's always been good parenting 101 - take your vitamins. Well, as time has gone on and more and more data has come forth. That old adage is no longer as sound advice as you would have hoped.
Taking a look at the Centrum website, you can see there's quite a bit that goes into a typical multivitamin. There's a lot to take in but I'm going to try and break down the evidence first by specific vitamin and then by multivitamins as a whole. I'll be skipping Vitamin D because that's a completely different discussion. In addition, I'm only including the most up to date studies for Cochrane since they have changed so many times in the past 10 years.
- Vitamin A
- 2012 Cochrane review: Possible increase in all-cause mortality (78 RCTs) [1]
- Vitamin E
- 2012 Cochrane review: Possible increase in all-cause mortality (78 RCTs)
- Vitamin C
- 2012 Cochrane review: NO increase in all-cause mortality (78 RCTs)
- Selenium
- 2012 Cochrane review: NO increase in all-cause mortality (78 RCTs)
- Beta-carotene
- 2012 Cochrane review: INCREASE in all-cause mortality (78 RCTs)
- Multivitamins
- 2013 Meta-analysis: NO increase in all-cause mortality [2]
- 2012 RCT (Physicians' Health Study II): NO increase in all-cause mortality for older men. Reduced cancer incidence only if hazard ratios were adjusted. [3]
- 2011 large observational trial (Iowa Women's Health Study): 2.4% absolute risk increase in all-cause mortality in older females. [4]
Looking at the most recent evidence, there really isn't a good reason to take multivitamins or specific supplements if you're a nourished, healthy individual in the developed world. In the end, there's a possible risk of mortality increase with certain supplements or for certain demographics and it's just another pill you have to take every day.
Verdict: Don't take them unless you have a documented nutritional deficiency or live in an area with nutritional deficiencies.
Fish Oil
Fish oil - the multivitamin of the adult. If it's not your mother then it's probably a family member or friend that has told you to take fish oil supplements. Like all vitamins or supplements, fish oil has been proposed to protect the body in a number of ways. For the sake of time and my sanity, I'm just looking at coronary heart disease as it's the main indication.
The first fish oil study was based off of the fact that Greenland Eskimos had low rates of coronary heart disease. Their high fish diet led them to do a 20 year observational study showing a 50%+ reduction in CHD in those who ate 30g of fish per day versus those who didn't. [5] This was bolstered by large meta-analysis of cohort and randomized trials in 2006, which found a 36% reduction in coronary deaths in those with "modest" fish consumption (1-2 servings/week). [6]
This leads us to the latest systematic review in JAMA 2012 that found that neither fish oil supplements nor eating extra servings of fish had any benefit with all-cause mortality, cardiac death, sudden death, MI, or stroke. [7] This was somewhat of a surprise since a healthy number of the participants had pre-existing CHD. One caveat that people much smarter than myself found was that there was actually a statistically significant 10% reduction in cardiac death in those that consumed omega-3 supplements. However, this benefit disappeared once they adjusted comparisons. I decided not to look in depth into the comparisons because I'm out of ibuprofen.
Verdict: Jury is still out. In the meantime, probably safe to take fish oil supplements high in EPA and DHA. Better yet, just eat some fish.
Bonus: There is limited data on the effects of fish oil on healthy adults without CHD. Study due in 2016 may answer this.