Dispelling nutrition myths, ranting, and occasionally, raving


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Is organic milk really better than conventional milk?

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Last week it was all over the news that organic milk is nutritionally superior to conventional milk. Don’t you just hate that non-organic is commonly known as “conventional”? When did the use of pesticides, herbicides, insecticides, and genetic modification become conventional anyway? I really think that we should have a more nefarious name for it. Anyway… I digress. The purpose of this post is not actually to bash non-organic farming. Nope, not today. Today I want to rant about this study.

First off, who sponsored the research? Oh, just CROPP, only the “nation’s largest and most successful organic farmer cooperative” according to their website. Oh sure, they had no influence over the design and results of the study but do you think it would have been published if it hadn’t found that organic milk was superior to non-organic milk? This is not unbiased research.

And let’s just talk about the finding that organic milk is much better for you than non-organic milk. The newspapers were reporting that organic milk contains significantly more omega-3 fatty acids, and significantly fewer omega-6 fatty acids, than non-organic milk. So, we should all drink more full-fat organic milk to obtain our omega-3s. Now, scientific significance is a funny thing. In this case it showed that there was a bit more than twice as much omega-3 in the organic milk, and about 1/4 as much omega-6. Wow! That’s a HUGE difference! Is it though? When we’re comparing 0.0321 g of omega-3 in organic milk and 0.0198 g in non-organic milk (per 100 g). No, no it’s not. And when we read the small print at the bottom of the graph stating that the results were biased because unreported small values were entered as zero this could make for a comparatively large margin of error. Especially when the researchers reported that they obtained more samples of organic milk than non-organic. This could quite easily have skewed the results to make the values appear lower in the non-organic than in the organic.

As the researchers point out, there was a great deal of seasonal variability in the fat-profile of the organic milk. This indicated that the increased omega-3, and decreased omega-6, was more likely a result of consumption of a grass and forage based diet rather than a grain-based diet. Basically, the miniscule benefit from consuming organic milk is a result of the diet composition, not the fact that it was organic.

I’m a big supporter of organic food and products. However, from a nutritional standpoint, there is little reason to choose organic milk over non-organic. There may, however, be some reason to choose grass-fed dairy products over grain-fed dairy.


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Omega-3-6-9

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Based on some things I’ve seen lately, I thought it was time for a little omega refresher.

Omega-9 fatty acids: These are non-essential fatty acids as our bodies are capable of synthesizing them. This means that a dietary source is unnecessary. Don’t be fooled into buying a 3-6-9 supplement.

Omega-6 fatty acids: These are essential fatty acids; our bodies are not capable of synthesizing them so we must obtain them from dietary sources. Omega-6 FAs are plentiful in most of our diets and, therefore, don’t require supplementation. We get Omega-6 from plant oils, nuts, and seeds. In fact, we get so much Omega-6 that it may be having negative effects, such as increasing inflammation. We should be consuming a ratio of 2:1 to 4:1, Omega-6 to Omega-3. However, many of us are consuming in excess of 14-25 times more Omega-6 than Omega-3 (1)!

Omega-3 fatty acids: These are also essential fatty acids. In order to obtain enough Omega-3 we only need 2-4 teaspoons of plant oils a day. This is where it gets tricky. You’ll see a lot of foods marketed as being good sources of Omega-3, more than salmon for example, but they neglect to mention that we also need to consume EPA and DHA, two forms of Omega-3 which are not available from plant-based sources. Plants can provide us with plenty of ALA, which was can modestly convert to EPA and DHA. However, the conversion rate is pretty minimal. Under optimal conditions (such as when we’re not also consuming excessive quantities of Omega-6) conversion can reach up to about 4%. Not great when it’s advisable to consume 0.3-0.5 grams of EPA and 0.8-1.1 grams of DHA per day (2). It’s best to obtain these by eating fatty fish (e.g. salmon, tuna, sardines, herring, mackerel, or trout) twice a week. If you don’t consume fish regularly, it may be worthwhile considering taking an Omega-3 supplement that contains both EPA and DHA as it’s pretty much impossible to get as much as you need by converting plant sources.

 


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Of mice and omegas

Apparently the anti-omega-3 supplement trend is continuing. The latest piece of research comes from BC and shows that, in combination, omega-6 and omega-3 polyunsaturated fatty acids may be increasing inflammation in the body. The study concluded that omega-3 supplementation could be increasing gastrointestinal distress in the elderly. According to a news article quoting the lead author, “levels of omega 6 are so high in our bodies that any more unsaturated fatty acid — even omega 3, despite its health benefits — will actually contribute to the negative effects omega 6 PUFA have on the heart and gut”.

I don’t dispute the likelihood that many of us are now consuming too much omega-6. However, this study is not affecting my decision to take omega-3 supplements. As a dietitian, I know that it’s better to get my nutrients from food and I should be eating more fish. Because I don’t eat as much fish as I should, I take an omega-3 supplement.

Why isn’t this study influencing my decision to pop an omega-3 supplement every second day? Well, the study was done on mice and recent evidence shows that mice studies may not be the best models for humans. In addition, the mice were fed a high fat diet (40% of total calories) with fat coming from canola oil and corn oil, with some mice being given fish oil as well. From where I sit, this is not much of an approximation of my fat consumption and I’m sure that applies to many of you as well. I get fat from olive oil, butter, dairy products (especially yoghurt and cheese), nuts and nut butters, coconut oil, eggs, etc. Very little of my fat intake comes from canola or corn oil. In addition, 40% is quite a high intake of calories from fat – the Acceptable Macronutrient Distribution (AMDR) for fat is 20-35% of total calories.

If you are consuming all (or most) of your fat from canola and corn oil and you’re eating a high-fat diet (and if you’re a mouse) then perhaps this study should give you pause before you decide to start taking an omega-3 supplement. However, I think that you should be more concerned about the excessive consumption of a limited variety of fats than you should be about adding omega-3 PUFAs to the mix.


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Time to toss those omega-3 supplements?

According to a new study we should all toss out our omega-3 supplements. This study found that there was no association between omega-3 supplementation and risk of death from cardiac events nor stroke. I’m not convinced enough to stop taking my supplement yet though.

Dietitians, and other health care professionals, have been encouraging omega-3 supplementation for those who do not consume enough (2-3 servings) fatty fish (e.g. salmon, sardines, mackerel) for a number of years. Previous studies have found that people who consume more of these types of fish have decreased risk of death from heart disease and stroke.

The problem lies in the fact that no supplement can compensate for a poor diet. If you’re consuming red meat and high levels of omega-6 (as most North Americans are) then you’re not likely to benefit from taking an omega-3 supplement. In the studies where consumption of fish was increased there was also a corresponding decrease in consumption of meat.

I’m going to continue to take my omega-3 supplement just because I know that I don’t eat enough fish. However, I also eat very little meat. The other reason that I’m going to continue to take my supplement is that there is a possibility that there may be other benefits to omega-3 supplementation beside cardiovascular health. Although current research is inconclusive, there may be benefits to mental well being.

I’m not suggesting that everyone should take an omega-3 supplement. If you can eat more fish, and less meat, you’d be much better off doing that.