Dispelling nutrition myths, ranting, and occasionally, raving


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Can peanut consumption prevent allergies?

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Last week the headlines all boasted that feeding babies peanuts could prevent peanut allergies. A new study in the New England Journal of Medicine assigned children thought to be at high risk for peanut allergy development to either an exposure group or an avoidance group. It was found that 10.6% of the infants in the exposure group tested positive for peanut allergy at 60 months of age, versus 35.3% of infants in the avoidance group. I’m not quite as convinced as the headlines that this is a cure for peanut allergy. Certainly, there was a large difference between groups. However, we have seen in previous research that peanut exposure in allergic children may increase tolerance, although not to the extent that they would be able to safely munch on a peanut butter and jam sandwich for lunch.

This may be a matter of semantics, and it’s purely my own interpretation, but I think that the current study provides more support for the stance that peanut (and likely other allergens) avoidance in at risk children increases the likelihood of allergy development. More so than the consumption of peanuts decreases the risk of peanut allergy.

Peanut allergy does not occur upon the first exposure to peanuts. It usually occurs upon the second exposure. Although it may occur upon subsequent exposures, this is unlikely in the case of peanut allergy. I can’t help but wonder how this may have effected the results. The authors don’t mention whether or not the infants in the study had been exposed to peanuts prior to enrolment. I can’t help but wonder if this could have affected the results in some way. There is also the question as to whether the withdrawal of infants from the study was a result of the development of peanut allergy in the consumption group, or perhaps discovery of the absence of allergy in the avoidance group. Could this have significantly affected the results? Adherence was quite good, over 90% in both groups, however, reasons for withdrawal could still have an impact on the results.

While the infants included in the study were all identified as being at risk of developing peanut allergies due to either the presence of eczema and/or egg allergy, these are not necessarily the best ways to identify risk. The children at greatest risk of developing peanut allergy are those who have an immediate family member (i.e. a parent or sibling) who has a peanut allergy. The children in the study would be at greater risk than those without eczema or other allergies but they would not necessarily be those at greatest risk. Perhaps infants at greatest risk would benefit from early peanut exposure, perhaps not. Perhaps infants in the general population would benefit from early peanut exposure, perhaps not.

Okay, so, I’m sure that parents are wondering what all of this means. Firstly, what many of the news articles are failing to impart is that the current guidelines recommend waiting until 6 months of age before introducing solids. Introducing peanuts, or any solid foods, at younger ages is not recommended as infants do not have fully developed digestive systems. Peanuts and peanut butter may also be choking hazards for infants, please be sure to use age appropriate foods and supervise your infant during feeding. Finally, this research supports the current guidelines which indicate that there is no reason to avoid providing your infant potentially allergenic foods at the same time that you introduce other foods. Regardless as to whether or not early introduction reduces the risk of allergy development or later introduction increases risk, at this point we know that there is no benefit to waiting, and there may be disadvantages to doing so.


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Children of the Quorn

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I found this post by CSPI (the Centre for Science in the Public Interest) calling for the ban of Quorn products in the US a little puzzling.

For those wondering, apparently Quorn is a “vat grown fungus” used in vegetarian meat product substitutes. Yes, I know, it sounds revolting to us omnivores. Personally, I think that plants (and I suppose fungi) should be proud to be themselves and not masquerade as meat. Putting that aside, apparently it’s quite popular. It’s not available in Canada because the CFIA has not tested, and therefore, not approved it for sale, as far as I can tell.

The FDA has approved the sale of Quorn products in the US but, based on reports of allergic reactions, the CSPI is calling for retailers to stop selling Quorn and for people who have experienced allergic reactions to report them to CSPI. If Quorn is toxic then, yes, it should not be sold. However, I can’t quite comprehend limiting the sale of a food simply because some people are allergic to it. Why not call for grocery stores to stop carrying peanut butter, soy, scallops, or any other common allergen?

Consumers should be aware that consuming Quorn may cause them to have an adverse reaction. They can make their own decisions from there. Unless there is more reason than this to believe that Quorn poses a significant risk, I say let the vegetarians eat their Quorn.


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I don’t think you’re ready for this gelatin

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Apparently gelatin is the latest “superfood”. Yep, the stuff in jello. Of course, you have to take away the added sugar, colour, and flavour for it to ascend to “superfood” status. You all know how I feel about “superfoods”. They’re a super scam. Sure, many of them are nutritious (think avocados and blueberries) but there’s nothing about them that makes them superior to other fruits and vegetables.

Okay, even if gelatin isn’t a “superfood” is it exceptionally good for you? Should we all be eating plain jello or taking gelatin capsules? Let’s take a look at the specific claims in the article…

Improved digestion – According to pretty much every wellness blog and self-proclaimed nutritionist gelatin improves digestion. However, as far as I can tell there is no scientific basis for this claim. I can’t find any research on the topic. This isn’t to say that gelatin doesn’t help digestion, but we don’t currently have any reason to believe that it does. 

Reduced food intolerance and allergy – This is a frightening claim. It would be lovely if it were true; people with peanut allergies could eat some gelatin and then chow down on some peanuts. And what about those people who suffer from gelatin allergy?

Strong bones and flexible joints – Because gelatin is made from animal cartilage (unless it’s the vegetarian variety which is made from seaweed) it’s easy to see how people draw the connection between gelatin and joint and bone health. However, despite this widespread belief, there’s no evidence to support the use of gelatin for bone and joint health. The same applies for Thick hair, strong nails and healthy teeth. Just because a substance (e.g. collagen) acts to strengthen our hair doesn’t mean that it will do so if we consume it orally. Otherwise, we would be able to improve our eye sight by eating eyeballs. A bit of an exaggeration, but you get the point.

Ageless skin – See the last point above. I’d also like to add that skin ages! Sorry, no matter what supplements we take, and what lotions and potions we apply we are all going to get wrinkles. Want to retain your youthful complexion for as long as possible? Eat a healthy diet with a variety of fruits and vegetables and fluids, get enough sleep, exercise, avoid tanning and sunburns.

Improved sleep – I was able to find one study that suggested that 2 grams of glycine ingested at bedtime improved subjective sleep quality. There’s 1.3 g of glycine in one serving of gelatin so it’s possible that you might obtain some benefit from it. However, this quantity may not be present in capsules so before you go running out to buy them before bed you might want to make sure that you’re getting what you’re paying for.


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Hypoallergenic apples

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Continuing on with the apple-theme from yesterday; researchers have been working on growing hypoallergenic apples. One group has been working on genetically modifying apple trees so that they produce apples containing fewer allergens. Another team has been working on breeding apple trees so that they produce similarly hypoallergenic apples.

Honestly, I think this is kind of ridiculous. Putting aside the potential issues stemming from genetic modification, I still have quibbles with the efforts ti develop hypoallergenic apples. For one thing, apples are not a commonly allergenic food. For another, I think this is taking the wrong approach to the problem. I think research would be better put into determining why people develop allergies and figuring out how to prevent or cure the allergy itself. It’s similar to treating symptoms rather than the root cause of an illness. The problem is not the apple.


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Is the sun setting on vitamin D?

Researchers in Germany recently found that higher maternal levels of vitamin D during pregnancy translated to higher in utero levels of vitamin D for their babies. This in turn, was associated with greater likelihood of developing a food allergy by age two. This is interesting because vitamin D is one of the few supplements I advise pretty much everyone to take, at least during the winter months, as it’s highly unlikely that most of us are meeting the current recommendations via food consumption.

Looking at the original journal article, I couldn’t find any listed source of funding. Always the first thing I check when I’m looking for legitimacy of research. Next I checked to see how many participants there were, and how they were selected. There were 629 mother-child pairs, not too shabby. Participants were recruited from an existing cohort study entitled LINA (Lifestyle and environmental factors and their Influence on Newborns Allergy risk). I’m not sure how participants were recruited from the study, nor am I sure how participants for the original study were recruited. I can’t help but wonder if they were volunteers if there might be some selection bias that would skew the results. However, further along in the methods, the researchers state that the vitamin D levels were tested for 378 mother-child pairs. This is still not a bad sample size, but not nearly as good as it initially appeared.

Getting into the statistical analysis makes me wish I had cared more about learning and retaining statistical ability when I was in school. It’s interesting to note that vitamin D levels were strongly correlated with season. Maternal and cord blood levels of vitamin D peaked in August and were lowest in March. Also, only seven of the mothers took vitamin D supplements during pregnancy. 44% of the mothers were deficient in vitamin D, 26% were insufficient, and 30% had optimal levels. 50% of newborns had deficient levels of vitamin D.

Results were analysed by dividing the mother-child pairs into quartiles based on the mothers’ vitamin D levels. I find this a little suspicious. There are no details provided as to how many mother-child pairs were in each category, nor what the cut-off were for each quartile, and I’m not sure how fair it is to draw comparisons between the quartiles if the distribution (as was mentioned in the analysis) was not equal. The results do show significantly more diagnosed food allergies among children born to mothers in the 3rd and 4th quartiles (i.e. those with the highest blood levels of vitamin D during pregnancy). However, there were still only six in the 4th quartile and five in the 3rd, compared to three in the 2nd and one in the 1st. It’s also important to note that the “diagnosed” food allergy was reported by the mother on a questionnaire; diagnosis was not actually obtained by the researchers. This introduces an additional element of bias.

In the discussion the researchers acknowledge that there was a high level of participation from allergy sufferers which may mean that the results can’t be generalised to the entire population.

Because vitamin D levels were so strongly correlated with the seasons I wonder if there is some other seasonal factor which may be causing the increased rate of food allergies among the children. There may also be some other commonality among the mothers with higher levels of vitamin D which is leading to increased rates of food allergies among their offspring.

I do think that this research is interesting and warrants further investigation. However, I worry that studies like this may actually cause more harm than good. Vitamin D supplements for infants are important to avoid the development of rickets. I wouldn’t want any potential parents, or new parents, to interpret these findings as an indication that they shouldn’t be providing these supplements to their babies.

 

Thanks to one of my loyal readers for sharing the news article with me and for one of my twitter friends for hooking me up with the original journal article.