Dispelling nutrition myths, ranting, and occasionally, raving


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Are prenatal vitamins a waste of money?

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Last week the news that pregnant women don’t need vitamin supplements seemed to be all over social media. The articles were based on this review article published in the Drug and Therapeutics Bulletin. The authors concluded that based on the evidence, much of which was from research in developing nations, that women (in Britain) do not need to take prenatal vitamins.

They reached this conclusion based on examining studies of the effects of folic acid, vitamin D, iron, vitamin C, vitamin E, and vitamin A supplementation on birth outcomes. While they concluded that multivitamin supplements are unnecessary for women during pregnancy, they stated that there was strong evidence to support women taking folic acid supplements and vitamin D supplements during pregnancy.

The message that came across most strongly (from the news articles) to me was that women are being shamed into purchasing vitamins that they can ill-afford, and don’t need, under the guise of wanting the best for their baby. The implications of these news articles concern me.

Firstly, women should be aware that many pharmacies (in Canada at least) have prenatal programs through which pregnant women can receive free multivitamin supplements, amongst other things. An inability to afford multivitamins should not prevent women from receiving them. Let’s not make this about drug companies trying to make money from poor women desperate to do the best for their unborn children. This should be about doing the best for women and their unborn children.

Okay, now that, that’s out of the way… I worry that the message that women should still be taking folic acid supplements and vitamin D supplements (and not just pregnant women I should add as most women of childbearing age should be taking folic acid supplements and most women in North America at least, should be taking vitamin D during the winter months) will be lost amid the cry that multivitamins are unnecessary. The message is not that all vitamin supplements are unnecessary for most Western women during pregnancy, just that the current evidence doesn’t support the use of multivitamins.

I’d also like to note that the researchers were focussing on birth outcomes. The conclusion that multivitamins are unnecessary was based on whether or not mums gave birth to healthy full-term babies. The authors did not take into consideration any potential long-term benefits maternal supplementation might have on their children. The authors did not take into consideration benefits that multivitamin supplementation might provide to mums. They did note that multivitamins can lower the mums risk of anemia, but as that didn’t seem to affect birth outcomes iron supplementation was deemed unnecessary. There are many other vitamins and minerals in multivitamins that the authors didn’t look at. Quite likely there’s not enough research on them to make a call either way. Regardless, the needs of pregnant women, not just their babies, should be taken into consideration when determining whether or not supplements are needed. Not all mums are going to get all the nutrients they need from food. Especially if they’re suffering from “morning” sickness. Perhaps not all mums will benefit from taking multivitamins. However, some very well may, and I think it would be a shame to tell them that they’re “wasting their money”.

Finally, as my friend Mark (who asked me to write about this topic) mentioned, taking two pills is more effort than taking just one. If it’s still being recommended that women take folic acid and vitamin D during pregnancy then they may as well just get those nutrients from a prenatal multivitamin rather than buying separate bottles of two supplements and having to remember to take both pills. It may be ever so slightly less expensive to buy vitamin D and folic acid instead of a multivitamin but I can’t even be certain of this because there was no folic acid for sale at my local grocery store when I went to price them all out. Which raises the issue of availability as well.

Women shouldn’t be made to feel guilty about not being able to afford a prenatal multivitamin. They also shouldn’t be made to feel like they’re wasting their money by buying them.

 


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Blog by request: folate

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Lacking in blogspiration, I went back through my inbox and realised that I had a few topic suggestions that I’d never written about. While this isn’t my usually ranting hopefully it will be useful information to some!

So… folate/folic acid, what is it?

Folate refers to the generic name for the vitamin as well as the various forms found naturally in foods. Folic acid is the form of the vitamin found in supplements and fortified foods. Naturally occurring folate usually has additional glutamate molecules attached that can reduce absorption as they need to be removed before the folic acid can be absorbed in the intestine.

What does folic acid do?

The main reason that the government introduced mandatory fortification of white flour with folic acid is due to the role it plays in preventing neural tube defects in infants. While prenatal vitamins contain folic acid many women don’t begin taking them until after they learn that they’re pregnant. This is often too late to promote proper neural tube development. However, as bread and other refined grains are widely consumed, the government decided to have it added to most refined grain products.

Folic acid plays an important role in DNA synthesis and repair as well as in the formation of neurotransmitters. It’s also involved in amino acid metabolism and blood pressure normalization.

How much folate do I need?

The RDA (recommended Dietary Allowance) for adults is 400 mcg a day. However, about 10% of the North American population has a defect in folate metabolism and may need up to twice the RDA to compensate. The RDA is based on the amount of folate needed to maintain normal blood concentrations as well as to prevent neural tube defects during fetal development.

Where do I get folate?

As mentioned above, most refined grain products and flours are fortified with folic acid. This includes breakfast cereals and dried pasta. Foods naturally containing folate include dark leafy greens (e.g. asparagus, spinach, romain lettuce, broccoli, brussels sprouts, and kale), lentils, peas (black-eyed peas, chickpeas), beans, turnips, beets, orange juice, sunflower seeds, avocado, edamame, okra, artichoke, potatoes, papaya, marmite and vegemite, and everyone’s faves: fried liver and brewer’s yeast.

This list, while extensive, may not include all food sources of folate. You can search for food items using the USDA Nutrient Database to find out how much folate they contain. Yes, Canada has a similar database but I’m not confident it’s entirely up to date and I find it  little bit more frustrating to use.

What happens if I don’t get enough?

Folate deficiency can result from low intake, inadequate absorption (often due to alcoholism), increased need (often due to pregnancy), poor utilization (often due to vitamin B12 deficiency), excessive excretion (often due to long-standing diarrhea), and the use of certain chemotherapy medications.

One of the first signs of folate deficiency is a form of anemia called megaloblastic anemia. It may also result in persistent diarrhea and decreased immune function.

If insufficient folate is consumed or absorbed during the first 28 days of pregnancy there is an increased risk of the infant experiencing neural tube defects (i.e. spina bifida or anencephaly).

Can I get too much folate?

The upper level for synthetic folic acid is set at 1000 mcg due to its ability to mask B12 deficiency when consumed in high doses. There is no upper level given for folate naturally occurring in foods as absorption is limited.


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Everything you want to know (and probably more) about vitamin K

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No ranting today. No raving either. A little while ago, a friend asked me to write a post about vitamin K-rich foods. So, this post is just straight-up info for those who are interested in learning more about vitamin K.

You may be wondering, “What is vitamin K?” (if you’re not, feel free to skip on ahead to the next paragraph). Vitamin K is a family of compounds including phylloquinone (vitamin K1) which is found in plants, and menaquinones (vitamin K2) which are found in fish oils and meats (thanks old nutrition textbook: Perspectives in Nutrition by Wardlaw and Hampl).

Vitamin K is essential for blood clotting. Fun fact: the Danish researcher who discovered the relationship between vitamin K and blood clotting named it for the word “koagulation” (which, in case you couldn’t guess, translates to “coagulation” in English). The adequate intake for women is 90 mcg a day, for men, 120 mcg, based on typical adult intakes. In addition to food sources of vitamin K, microorganisms in our intestines also produce vitamin K.

Although, vitamin K is a fat soluble vitamin, there is no upper limit set for consumption as it tends to disappear from the body within a few days of consumption. However, high dose supplements are not recommended as the synthetic form of vitamin K is far more potent than the naturally occurring forms as has been found to cause hemolytic anemia in rats and severe jaundice in infants. Vitamin K deficiency is also relatively uncommon. It’s most likely to be seen in people who have fat malabsorption (e.g. celiac disease or some types of bariatric surgery), long-term antibiotic use, or seniors with little consumption of leafy green vegetables. Newborn infants are routinely given vitamin K injections within 6 hours of delivery as they are at risk of defective blood clotting and hemorrhaging as a result of vitamin K deficiency. It’s important for people taking blood thinners, and some other medications, to consume consistent (or limit) amounts of vitamin K containing foods to ensure efficacy of the medications.

As alluded to above, leafy greens are the primary dietary source of vitamin K. Kale tops the list at 530 mcg per 1/2 cup (cooked), followed by turnip greens (520 mcg per cup), spinach (480 mcg/cup), brussels sprouts (150 mcg per 1/2 cup), raw spinach or cooked asparagus (144 mcg/cup), cooked broccoli (110 mcg for 1/2 cup), and looseleaf lettuce (97 mcg/cup). Other good sources of vitamin K include: cooked green beans (48 mcg per 1/2 cup), raw cabbage (42 mcg/cup), sauerkraut (30 mcg per 1/2 cup), green peas (26 mcg per 1/2 cup), soybean oil (25 mcg/tbsp), and cooked cauliflower (20 mcg/cup).


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Leave the veg for the rabbits, you’re going to die anyway

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A few weeks ago, Dr Sharma shared this article (on twitter and on facebook), without comment. It’s an article by the dreaded Zoe Harcombe about why we shouldn’t be striving for at least five servings a day of fruit and vegetables. No, it’s not what you think. She’s not suggesting that people should have more than 5 servings of veg and fruit a day, she’s suggesting that people should have fewer servings of veg and fruit a day. “Great,” I thought, “Zoe strikes again“.

After working myself up into a bit of a rage about the article I noticed the date on it. January 2011. When I first saw that I thought that I wouldn’t blog about it after all as it’s not current. My second thought was, “whatever”. If I’m only seeing this for the first time there are probably others only seeing it for the first time as well.

Harcombe argues that recent research showing the lack of protection against myriad chronic diseases through increased vegetable and fruit consumption means that we should cease encouraging people to eat more vegetables and fruits. And everyone rejoiced and ate doughnuts for dinner and lived long and healthy lives dying peacefully from old age in their sleep! Dietitians, nutritionists, and other health professionals were suddenly out of work as there was no more chronic disease to contend with. If only.

In the article, Harcombe states, “no doubt some dieticians and nutritionists will reject my arguments. But science backs me up.”
Well, she got the first part of that statement right, at least.

A great deal of Harcombe’s hypothesis centres around the assertion that vegetables and fruit don’t contain many vitamins or minerals. She concedes that vegetables do contain vitamin C and some A and K. Fruit apparently is only good for potassium. According to Harcombe, meat and other animal products are superior sources of most vitamins and minerals. This truly is a load of nonsense. Veg and fruit can be good sources of many vitamins and minerals. Not to mention the fact that they are usually good sources of water and can provide greater volume to your meal with few calories. Food is not just about individual nutrients. It’s about taste and texture and pleasure. Imagine eating a salad without vegetables. Think about the pleasure of eating a fresh blackberry off the brambles. How dull food would become if we didn’t have vegetables and fruit in our diets.

Harcombe moves on from her argument about the lack of vitamins and minerals in vegetables and fruit to say that some dietitians will argue that they are a source of antioxidants. She doesn’t object to this statement but instead says that she would rather not ingest oxidants in the first place. What was it that she said earlier? Oh yeah, “Science backs me up.” Might be time for a review of the oxidizing process, Zoe. If she’s avoiding oxidizing agents I want to know how she’s managed to survive without breathing air or drinking water. Our environment is chockfull of oxidizers. We should certainly avoid adding to them ourselves by avoiding smoking, excessive sun exposure, excessive alcohol consumption, etc. However, avoiding “chemicals” as Harcombe suggests is both ridiculous and impossible. Everything is chemicals. We are chemicals.

There is too much in this article to address it all. I mean, I could, but it’s too nice out as I’m typing this, and would you really keep reading if I went on and on? I just want to touch on one more issue with Harcombe’s vendetta against vegetables and fruit.

Harcombe takes issue with the belief that vegetables and fruit are important sources of fibre in our diets.

“The fact is, we can’t digest fibre. How can something we can’t even digest be so important to us, nutritionally?”

Apparently Harcombe doesn’t mind being constipated. Nor does she recognise the importance of fibre in prevention of heart disease. The desire to feel satisfied after a meal? Also not important. Even if these things are not important to her fibre serves other important organisms inside our bodies. That indigestible fibre is food for the bacteria living in our digestive tracts. Those same bacteria that provide us with things like vitamin B12, protect us against GI upset and harmful micro-organisms. We’ve only just begun to scratch the surface of the importance of our gut bacteria but it seems that they do a lot more for us than we ever realised.

So, if we are to listen to Harcombe and throw those five-a-day away, what are we to eat? Her top five foods: liver, sardines, eggs, sunflower seeds, and dark-green vegetables. That’s right. After telling us that vegetables and fruit are overrated and should be left for the rabbits, Harcombe then turns around and recommends vegetables in her top five foods. I rest my case.