Dispelling nutrition myths, ranting, and occasionally, raving


7 Comments

The harm in fad diets

Many of us roll our eyes when we hear about people on fad diets. I think that most of us think, “oh well, it’s not doing them any harm. Let it run its course”. But what if these diets are doing people harm?  I’m not about fear mongering, you know this. Many of these trendy diets can be safe and healthy when followed properly. However, what about when they’re not? There is reasonable risk of deficiencies that could cause some degree of harm at worst, and at best prevent the adherents from attaining optimal health.

What’s the harm in a low-carb or gluten-free or paleo diet?

I’m lumping these two in together even though they’re not strictly the same, although it seems that they frequently go hand-in-hand. Here the risk lies in B vitamin deficiency. Yes, many B vitamins are available from animal foods. However, folic acid (which I blogged about a few weeks ago) was added to refined flour and cereals as a public health measure to prevent neural tube defects during pregnancy in 1998 (1). Eliminating grains from the diet may lead to increased risk of spina bifida, and other neural tube defects, in infants of mothers following these diets. It’s recommended that all women of childbearing age take a multivitamin containing 400 mcg of folic acid daily. Women who are following the above diets should be sure to follow this recommendation. The crucial window for neural tube formation is within the first 21-28 days of pregnancy. This means that if you wait to start taking a prenatal multivitamin once you find out you’re pregnant you may have already missed this window.

What’s the harm in a vegan diet?

While touted as one of the healthiest diets, a vegan diet can easily be deficient in essential nutrients. As with the low-carb diets above, a vegan diet may be low in some B vitamins. In this case, vitamin B12 is more likely to be the B vitamin of concern than is folic acid.

Vitamin B12 is important for many reasons. We need B12 for blood cell formation, nerve function, and brain function.

Vitamin D is also a concern in vegan diets as it’s primarily found in milk, fish, and eggs. During the winter months it’s difficult for most of us, vegans and non-vegans alike, to get enough vitamin D from food alone.

What’s the harm in a low-sodium diet?

This isn’t even so much a risk of low-sodium diet but of a diet that eschews table salt in particular. Now that sea salt is the salt selection of foodies and many of us are avoiding salt shakers there is potential for insufficient iodine consumption. Table salt is fortified with iodine, sea salt is not.

Iodine deficiency during pregnancy can result in poor mental development. Iodine is important in thyroid function and deficiency may result in the development of a goiter.

Now, to be fair, when consideration of balance, variety, and nutrients is taken into consideration all of these diets may be healthy. I think that it’s also worth mentioning that the average Western diet is probably less nutritious than all of the above diets. Most people consume too few vegetables and fruits, too much sodium, sugar, and fat. Most of us, even those of us consuming relatively healthy diets, don’t get enough potassium, vitamin D, magnesium, and fibre. While the focus should definitely be on whole food, it’s worth considering what nutrients your diet may be low in and making an effort to consume more foods rich in those nutrients or even considering taking a supplement if you’re finding it hard to meet your nutrient needs through food alone.


6 Comments

What you need to know about magnesium

5864314419_f9057eec1c_z

Photo “nuts!” by Adam Wyles on Flickr, used under a Creative Commons Licence.

I recently read an article about magnesium that someone shared on facebook. Shockingly, for FB, it wasn’t nearly as inaccurate as I had expected. However, there were a couple of things in it that I wanted to address. The premise of the article was that most of us are magnesium deficient. This is untrue. Most of us don’t consume enough magnesium but there’s a world of difference between that, and being truly deficient. Magnesium deficiency manifests as an irregular heartbeat which may be accompanied by weakness, muscle spasms, disorientation, nausea, vomiting, and seizures. People who are at greatest risk of magnesium deficiency include: users of some diuretics, those with diabetes, people with alcoholism, as well as those who live in climates where they experience frequent heavy perspiration or those who have long bouts of vomiting or diarrhea.

So, how much magnesium should you be consuming? If you’re a man between 19 and 30 years of age, you should be consuming about 400 mg a day. Women in this age group should be consuming about 310 mg a day. Needs increase beyond this age by about 20 mg/d for men and 10 mg/d for women, and for those experiencing the conditions listed above. For more information of magnesium recommendations, click here. According to one of my old nutrition textbooks (Perspectives in Nutrition by Wardlaw and Hampl), assuming things haven’t changed that much in the past eight years, men consume 325 mg, women 225 mg, on average each day.

It’s not that terribly difficult to reach the recommended intakes of magnesium. One cup of spinach contains 157 mg, one cup of squash `105 mg, 1/4 cup of wheat germ 90 mg, 1/2 cup of navy beans 54 mg, 1 cup of plain yoghurt 43 mg… Nuts and seeds are also good sources of magnesium; as is dark chocolate and raw cacao (nibs, powder). Other leafy greens, beans, and legumes are also good sources of magnesium.

If you do decide to take a magnesium supplement, you should be aware that they are not all the same. Magnesium oxide tends to be the most common and inexpensive form of supplemental magnesium. However, it is also the most poorly absorbed form of magnesium. Liquid magnesium supplements will be best absorbed; the quantity of magnesium listed on the label is not as important as the form. As far as tablets and capsules go, Magnesium lactate, magnesium gluconate, and magnesium citrate are the most absorbable. However, magnesium citrate may have laxative effects, and magnesium hydroxide and magnesium sulfate are forms commonly used as laxatives. Zinc supplementation may interfere with magnesium absorption, while vitamin D supplementation may enhance magnesium absorption. Some medications may also affect magnesium absorption. As with any supplement, you should always check with your pharmacist to ensure that there will be no interactions with any other medications you’re taking. As with any nutrient, it’s best to try to get it from your food rather than from a supplement.


1 Comment

Do you need a testosterone boost?

url

A friend recently sent me a link to this article Why Testosterone Is Your FriendMy first question was: is testosterone deficiency a common problem. This study puts the prevalence at roughly 10% in males aged 20-79. However, deficiency was much more common among the older males. Testosterone deficiency may also be a problem for women. Naturally, the research in this area lags far behind that of the research on men so it’s impossible for me to comment on the need for testosterone boosting efforts in women.

The article is correct in stating that testosterone plays an important role in the body. It plays a role in sex development and libido, bone mineralization, weight and body mass composition, and energy levels (1). That being said, it’s relatively unlikely that a fit young person suffers from testosterone deficiency. If you do suspect that you suffer from testosterone deficiency, then you should visit your doctor. She or he will be able to measure you testosterone levels through blood tests. Pending the results, appropriate treatment efforts can be determined. Please don’t self-diagnose or take the advice of a fitness blog written by a personal trainer (or anyone, regardless of credentials as gospel).

Much of the advice in the post is solid advice for anyone regardless of testosterone levels. Indeed, obtaining an adequate nights sleep and reducing stress could benefit most of us. Let’s just quickly go through each of the suggestions…

1. Get deep sleep. Everyone can benefit from getting a solid nights sleep. Yes, this may help to increase testosterone.

2. Lift heavy things. Strength training is important for everyone to maintain muscle mass and bone density as we age. This may help to increase testosterone levels in people who are slightly low, but it’s unlikely to make much of a difference for anyone who’s deficient (2).

3. Don’t run too much. As someone who loves to run, I have a bit of a personal bias against this one. Run too much? Does not compute. Apparently, those who over-train, or elite athletes, may actually see a drop in testosterone levels. However, it would certainly take more than running a few times a week to have such an effect. If you enjoy running, don’t stop.

4. Eat fat, especially saturated fat. This is quite a vague recommendation. I certainly thing that fat has been unfairly vilified in the past (and sometimes, in the present). It is also possible that consumption of fat, and saturated fat may impact testosterone levels (3). However, these findings are based on a very small correlational study which makes it impossible to draw widespread recommendations from them. That being said, fat is an essential nutrient and (aside from man-made trans-fats) should not be avoided. There’s a good review of the research here. The AMDR for dietary fat is 20-35% of total calories for adults. Of course, our needs vary so you may fall on the low or high end of that scale depending on your genes and activity levels. Ignore the recommendation in the article to eschew plant oils. Use a variety of oils and fats.

5. Eat enough protein. Most of the research on protein and testosterone focuses on the inverse relationship. Again, a very small study found that ingestion of whey protein following a workout increased testosterone and androgen receptors in men (aged 57-72) while a placebo had no effect. Interesting. However, I would caution against extrapolating such a small study to younger men and women and even to all middle-aged men. While most of us consume more protein than we need, we may be well-served by consuming more consistent amounts at meals and snacks. Focus on getting more than 15 grams of protein at breakfast, protein at all meals and snacks, and meet with a registered dietitian if you have questions about adequate consumption of protein.

6. Keep stress levels low. Low testosterone and symptoms of stress may manifest in the same manner but there’s little evidence to support the assertion that stress will lower testosterone (4). Of course, stress is not good for us so taking steps to reduce stress in your life will likely serve you well regardless of your testosterone levels.

7. Don’t binge drink. Duh. Binge drinking is bad for your liver, your brain, and every other organ in your body. Animal studies suggest that chronic alcohol consumption may lower testosterone levels. It makes sense that if heavy alcohol consumption impairs bodily functions that it would also impair testosterone production. Despite the lack of human evidence, I’m not going to argue with this one. Don’t drink to excess, regardless of your testosterone status.

8. Get enough zinc and magnesium. There may be benefits to getting more zinc if you’re not getting enough in your diet. If you’re already getting enough, more is not going to help (5). Many of us don’t get enough magnesium in our diets so aiming to consume more magnesium-rich foods (e.g. nuts, seeds, beans, dark leafy greens, dark chocolate) is worthwhile. I wouldn’t recommend supplementing with zinc without first discussing with your doctor as zinc can interfere with the absorption of other minerals, like copper, and unnecessary supplementation could lead to deficiency in another mineral.

9. Make sure to get enough carbs. Personally, I love carbs. I’d never suggest anyone cut carbs from their diets. However, there’s no reason to believe that insufficient carb consumption will lead to testosterone deficiency.

10. Get enough vitamin D. Research on vitamin D has been mixed. Most of us can get enough from the sun in the summer months. We may benefit from supplementation of 1000 IU during winter months. Vitamin D may slightly increase testosterone in deficient males (6). As with most things, just because some is good, doesn’t mean that more is better. While uncommon, it is possible to consume toxic levels of vitamin D so don’t go mega-dosing.

11. Stay away from soy. Research looking at testosterone levels and soy consumption has focused on soy protein supplements. Results have been mixed. It’s quite unlikely that consuming soy in “natural” states (such as tofu, edamame, soy beans/nuts, or tempeh) is going to have any impact on your testosterone levels.

12. Eliminate wheat and gluten grains. Now we’re really going off the rails. There is no link between wheat and gluten and testosterone deficiency. There is no reason to eliminate gluten from your diet unless you have celiac disease or an allergy.

13. Limit all medications/birth control pills. Some medications may affect hormone levels. Some will not. Don’t stop taking essential medications and don’t take unnecessary medications. If you have any concerns about any medications that you’re on discuss them with your doctor.

There are also potential risks associated with high testosterone levels. Let’s not get carried away with focusing on low testosterone without first learning that our testosterone is indeed low.