A Practical Approach to Omega Fats

Hunter-gatherers and healthy non-industrial cultures didn't know what omega-6 and omega-3 fats were. They didn't balance nutrients precisely; they stayed healthy by eating foods that they knew were available and nourishing. Therefore, I don't think it's necessary to bean count omega fats, and I don't think there's likely to be a single ideal ratio of n-6 to n-3. However, I do think there's evidence for an optimal range. To find out what it is, let's look at what's been done by healthy cultures in the past:

• Hunter-gatherers living mostly on land animals: 2:1 to 4:1


• Pacific islanders getting most of their fat from coconut and fish: 1:2


• Inuit and other Pacific coast Americans: 1:4 or less


• Dairy-based cultures: 1:1 to 2:1


• Cultures eating fish and grains: 1:2 or less

It looks like a healthy ratio is between 4:1 and 1:4 n-6 to n-3. Some of these cultures ate a good amount of n-3 polyunsaturated fat, but none of them ate much n-6 [One rare exception is the !Kung. SJG 2011]. There are three basic patterns that I've seen: 1) low fat with low total n-6 and n-3, and a ratio of less than 2:1; 2) high fat with low total n-6 and n-3 and a ratio of 2:1 or less; 3) high fat with low n-6 and high n-3, and a low carbohydrate intake.

I think there's a simple way to interpret all this. Number one, don't eat vegetable oils high in n-6 fats. They are mostly industrial creations that have never supported human health. Number two, find a source of n-3 fats that can approximately balance your n-6 intake. In practical terms, this means minimizing sources of n-6 and eating modest amounts of n-3 to balance it. Some foods are naturally balanced, such as grass-fed dairy and pastured lamb. Others, like coconut oil, have so little n-6 it doesn't take much n-3 to create a proper balance.

Animal sources of n-3 are the best because they provide pre-formed long-chain fats like DHA, which some people have difficulty producing themselves. Flax oil may have some benefits as well. Fish oil and cod liver oil can be a convenient source of n-3; take them in doses of one teaspoon or less. As usual, whole foods are probably better than isolated oils. Weston Price noted that cultures throughout the world went to great lengths to obtain fresh and dried marine foods. Choose shellfish and wild fish that are low on the food chain so they aren't excessively polluted.

I don't think adding gobs of fish oil on top of the standard American diet to correct a poor n-6:n-3 ratio is optimal. It may be better than no fish oil, but it's probably not the best approach. I just read a study, hot off the presses, that examines this very issue in young pigs. Pigs are similar to humans in many ways, including aspects of their fat metabolism. They were fed three diets: a "deficient" diet containing some n-6 but very little n-3; a "contemporary" diet containing a lot of n-6 and some n-3; an "evolutionary" diet containing a modest, balanced amount of n-6 and n-3; and a "supplemented" diet, which is the contemporary diet plus DHA and arachidonic acid (AA).

Using the evolutionary diet as a benchmark, none of the other diets were able to achieve the same fatty acid profile in the young pigs' brains, blood, liver or heart. They also showed that neurons in culture require DHA for proper development, and excess n-6 interferes with the process.

With that said, here are a few graphs of the proportion of n-6 in common foods. These numbers all come from nutrition data. They reflect the percentage n-6 out of the total fat content. First, animal fats:


Except salmon oil, these are traditional fats suitable for cooking. Except schmaltz (chicken fat), they are relatively low in n-6. Next, vegetable oils:


These range from very low in n-6 to very high. Most of the modern, industrially processed oils are on the right, while most traditional oils are on the left. I don't recommend using anything to the right of olive oil on a regular basis. "HO" sunflower oil is high-oleic, which means it has been bred for a high monounsaturated fat content at the expense of n-6. Here are the meats and eggs:

n-3 eggs are from hens fed flax or seaweed, while the other bar refers to conventional eggs.

A few of these foods are good sources of n-3. At the top of the list is fish oil, followed by n-3 eggs, grass-fed butter, and the fat of grass-fed ruminants. It is possible to keep a good balance without seafood, it just requires keeping n-6 fats to an absolute minimum. It's also possible to overdo n-3 fats. The traditional Inuit, despite their good overall health, did not clot well. They commonly developed nosebleeds that would last for three days, for example. This is thought to be due to the effect of n-3 on blood clotting. But keep in mind that their n-3 intake was so high it would be difficult to achieve today without drinking wine glasses full of fish oil.

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Omega Fats and Cardiovascular Disease

I noticed something strange when I was poring over data about the Inuit last month. Modern Inuit who have adopted Western food habits get fat, they get diabetes... but they don't get heart attacks. This was a paradox to me at the time, because heart disease mortality typically comes along with the cluster of modern, non-communicable diseases I call the "diseases of civilization".

One of the interesting things about the modern Inuit diet is it's most often a combination of Western and traditional foods. For example, they typically use white flour and sugar, but continue to eat seal oil and fish. Both seal oil and fish are a concentrated source of long-chain omega-3 (n-3) fatty acids.The 'paradox' makes much more sense to me now that I've seen this:

It's from the same paper as the graphs in the last post. Note that it doesn't take much n-3 to get you to the asymptote. Here's another one that might interest you:

The finding in this graph is supported by the Lyon diet heart study, which I'll describe below. One more graph from a presentation by Dr. Lands, since I began by talking about the Inuit:


Cardiovascular disease mortality tracks well with the n-6 content of blood plasma, both across populations and within them. You can see modern Quebec Inuit have the same low rate of CVD mortality as the Japanese. The five red triangles are from MRFIT, a large American intervention trial. They represent the study participants divided into five groups based on their plasma n-6. Note that the average percentage of n-6 fatty acids is very high, even though the trial occurred in the 1970s! Since n-3 and n-6 fats compete for space in human tissue, it makes sense that the Inuit are protected from CVD by their high n-3 intake.  [Update: I don't read too much into this graph because there are so may confounding variables.  It's an interesting observation, but take it with a grain of salt.. SJG 2011].

Now for a little mechanism. Dr. Lands' hypothesis is that a high n-6 intake promotes a general state of inflammation in the body. The term 'inflammation' refers to the chronic activation of the innate immune system. The reason is that n-3 and n-6 fats are precursors to longer-chain signaling molecules called eicosanoids. In a nutshell, eicosanoids produced from n-6 fatty acids are more inflammatory and promote thrombosis (clotting) more than those produced from n-3 fatty acids. Dr. Lands is in a position to know this, since he was one of the main researchers involved in discovering these mechanisms. He points out that taking aspirin to 'thin' the blood and reduce inflammation (by inhibiting inflammatory eicosanoids) basically puts a band-aid over the problem caused by excess n-6 fats to begin with.  [Update- this mechanism turns out not to be so straightforward. SJG 2011]

The Lyon Diet Heart Study assessed the effect of n-3 fat supplementation on CVD risk. The four-year intervention involved a number of diet changes designed to mimic the American Heart Association's concept of a "Mediterranean diet". The participants were counseled to eat a special margarine that was high in n-3 from alpha-linolenic acid. Overall PUFA intake decreased, mostly due to n-6 reduction, and n-3 intake increased relative to controls. The intervention caused a 70% reduction in cardiac mortality and a large reduction in all-cause mortality, a smashing success by any measure.

In a large five-year intervention trial in Japan, JELIS, patients who took EPA (a long-chain n-3 fatty acid) plus statins had 19% fewer cardiac events than patients taking statins alone. I don't know why you would give EPA by itself when it occurs with DHA and alpha-linolenic acid in nature, but it did nevertheless have a significant effect. Keep in mind that this trial was in Japan, where they already have a much better n-6/n-3 ratio than in Western nations.

In my opinion, what all the data (including a lot that I haven't included) point to is that a good n-6 to n-3 ratio may be important for vibrant health and proper development. In the next post, I'll talk about practical considerations for achieving a good ratio.

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Nutella Swiss Roll

It was a rare occasion that I was blessed with so much free time that I felt asleep on a weekday afternoon. I guess I was not feeling well (yes, I'm trying to make myself feel less guilty) or it was just pure laziness that I didn't wake up until 2 hours later! As a result, I had to abandon my earlier plan to bake a loaf of bread as there wasn't much time left before I had to start preparing dinner.

After flipping through my stack of recipes, I thought I should make a Swiss roll. In the past, I always relied on a sponge cake recipe to make a Swiss roll. It was the first time I was going to follow a proper Swiss roll recipe. I didn't bother to use any whipping cream for the filling, as first of all, I was running out of time and secondly I am doubtful whether I'll be able to roll the cake without cracking it . Hence, to make things easy, I decided to use nutella spread to fill the roll.

The making of the sponge cake layer was rather straight forward, as there were only 5 ingredients used. There was little washing up as well, since everything was done with a mixing bowl. I was able to get the cake out from the oven in no time. While the cake was cooling on the rack, I got on with the tedious chore of cooking dinner :(


As with all my past attempts with Swiss rolls, I felt a little nervous when it was time to fill and roll the cake. I almost let off a whistle when the cake didn't crack upon rolling!


I am not sure it was just pure luck, or was it the technique outline in this recipe that made the rolling so easy. I guess I would have to try this again to verify. Some Swiss roll recipes that I have come across would recommend that the cake be rolled up while it is still warm. The cake would then be unrolled upon cooling, filled and re-rolled again. Whereas for this recipe, the cake is left to cool off before filling and rolling. According to the recipe, once the cake is out of the oven, it has to be removed from the tray and placed in a big plastic bag to cool off. This way, the cake will stay soft and moist for easy rolling. Since I do not have a large enough plastic bag, I left the cake in the baking tray and placed the tray on a cooling rack. To retain the moisture, I covered the top with another Swiss roll tray. Upon cooling, I was surprised that the sponge layer was not soggy or damp. I moved on to remove the parchment paper and turned the sponge layer onto a clean sheet of parchment paper. It was a little tricky trying to spread the nutella as it was rather thick, I had to be extra gentle to avoid scraping the crumbs as I worked along.

Besides retaining moisture when the sponge layer is cooling off, I think it is also important not to over bake the cake, otherwise it would be too dry and would crack easily. As usual, my unreliable oven took a little longer than the recommended time to get the sponge layer baked, and I had to turn the tray closer to the end of the baking time to ensure even browning.

In order to make a nice clean roll, another seemingly minor point to watch out for, would be the kind of paper used for rolling. I remembered using those greaseproof papers (or tracing papers which I used to call them when I was young!) when I first attempted to make a Swiss roll. The cake got stuck to the paper, as a result, the 'skin' got peeled off upon rolling/unrolling. I also used to wonder why my cookies would stick to this type of greaseproof paper upon baking. Until much later, I discovered those are not the right type of paper for baking. I have since switched to using proper parchment paper or baking paper which has got a layer of wax making them greaseproof and non-stick as well.


I was very satisfied with how well the sponge layer turned out, it was soft and moist, and what can I say about nutella? You will never go wrong with it ;)


Ingredients:
3 eggs, bring to room temperature
65g sugar (updated: use caster sugar)
80g cake flour
20g unsalted butter, melted
2~3 drops vanilla extract

Method:

1. Sift cake flour, set aside. Line a 9" x 12" (23 x 30cm) Swiss roll tray with parchment paper, set aside. Pre-heat oven to 180 degC.
2. With an electric mixer, whisk eggs and sugar on HIGH speed for about 5 to 7 mins, until the batter double in volume and is ribbon-like (the batter should leave a ribbon-like texture when the beater is lifted up). Turn to LOW speed and whisk for another 1 to 2 mins. Whisking at low speed helps to stabilise the air bubbles in the batter.
3. Add sifted cake flour into the batter in 3 separate addition. With each addition, use a spatula, gently fold in the flour until well blended. Take care not to deflate the batter.
4. Add the melted butter and vanilla extract, fold with spatula until well blended.
5. Pour the batter into the tray. Spread and smooth out the batter evenly. Bake for 10~15 mins*, until the surface turns golden browned or until a skewer inserted in the centre comes out clean.
6. Remove tray from oven. Remove sponge layer from tray (with parchment paper still in tack), place it in a plastic bag**. Tie the plastic bag and leave it to cool. (Instead of using a plastic bag, I cover the sponge layer with another Swiss roll tray.)
7. Upon cooling, remove the parchment paper, and turn the sponge layer with the 'skin' side down on a sheet of clean parchment paper. Spread with nutella (or any filling as desired) and roll up the sponge layer by lifting it up with the parchment paper. Place the rolled cake seam side down.

NOTE:
*Do not over bake the sponge layer, otherwise it will turn dry and may crack upon rolling.
** The reason for doing so is to keep the sponge layer moist for easy rolling.

Recipe source: 点心达人, 轻松学 / 小川智美著

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BACK TO SCHOOL TREATS

organic brown rice crispies squares with ground flaxseed

I know...I know. There's a ton of sugar in marshmallows and though Rice Crispies Squares seem pretty benign junk food-wise, they do have that ooey chewy marshmallow sugar-high factor that is oh so true to junk food.

Yes, the treats have cereal, but I personally don't think most of the cereals you find in the supermarket aisles are very healthy breakfast options because of the high sugar content. That being said, of course I feed cereal to my child occasionally. Perhaps once a week or once in two weeks, Bebe sometimes has Cheerioes multigrain cereal or her favourite cereal: Kellogg's Guardian All Bran cereal (primarily for the little heart shapes I think). Though these cereals have the fibre I so want to include in her diet, they also have a fair amount of sugar. Since she doesn't eat cereal everyday though, I don't think it's too much of a problem. In fact, I rarely police Bebe's intake of sugar and don't deprive her of a few jellybeans or M&M's if she wants them. You know I would never say "no" if she asked for cupcakes or dessert! She has pretty good self control and I've never seen her over-indulge in anything sweet. She's so not like mommy ;)

My mommified rice crispies treats have been doctored in as healthy a way as possible without compromising on the much-loved taste of the original recipe we all know. I used organic brown rice cereal, marshmallows, unsalted butter and freshly ground flaxseed in my rendition. Flax is so yucky on its own that I have to hide it somewhere and this is as good a place as any.

If you ate these treats, you wouldn't be able to tell the difference between the original recipe and the "healthy" one. The flax is not detectable. hm. Probably because of the marshmallow. Well, I tried. Doesn't that count?

So, if you want to feel less guilty about eating rice crispies squares, then by all means take the original recipe and add up to 1/4 cup freshly ground organic flaxseed and replace the regular rice crispies cereal with organic brown rice cereal. I don't think it's necessary to locate healthy marshmallows. I just used my favourite brand from the supermarket, but I suppose if you had the energy you could use homemade chocolate marshmallows as I have in the past. Homemade is always best and you can never go wrong by adding chocolate to stuff.

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Omega-3 Fats and Brain Development

Another interesting study that Dr. Hibbeln sent me is about the link between maternal seafood consumption and neurodevelopmental outcomes in children. The study is about as powerful as epidemiology gets, with an enrollment of 11,875 mothers.

The bottom line is short and sweet: compared to the children of mothers who ate 340 grams or more of fish per week, children whose mothers ate very little fish had an increased risk of low verbal intelligence, poor social behavior, poor motor skills, poor communication skills, and poor social development. These associations remained after adjusting for 28 potential confounders, including social status, level of education, stressful life events, smoking, alcohol, and several others.

In support of this association, in another study the four-year-old children of mothers who were given DHA and arachidonic acid supplements had higher IQs than those given "placebo" (corn oil). There have been a number of trials of varying quality that have shown varying results with n-3 supplementation, so I'll leave you to decide what you think of this. A 2007 review I found on n-3 supplementation and brain development states that "the evidence for potential benefits of LCPUFA [long-chain polyunsaturated fatty acid] supplementation is promising but yet inconclusive".

I do think it's interesting to note that the brain has the highest concentration of long-chain n-3 fats of any organ, and eating n-3 fats in the form of fish, fish oil or cod liver oil increases the amount in tissues. Eating too much n-6 depletes the brain of DHA and adversely affects neuron development in piglets. n-3 deficiency affects the release of serotonin (a neurotransmitter) in rat brains.

Put it all together, including the data from the last two posts, and I think there's some evidence that a good balance of n-3 to n-6 fatty acids is important for optimal brain function and perhaps development.

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The Omega Ratio

The theory advanced by Dr. Lands and Hibbeln is that the ratio of omega-6 to omega-3 fatty acids in the diet is the crucial factor for mental and physical health, rather than the absolute amount of each. Omega-6 and -3 fats are essential long-chain polyunsaturated fatty acids. The number refers to the position of the double bond near the methyl end of the carbon chain.

The ratio of omega-6 to omega-3 (hereafter, n-6 and n-3) in the diet determines the ratio in tissues. Since these molecules have many cellular roles, it doesn't stretch the imagination that they could have an effect on health. Hunter-gatherer and healthy non-industrial cultures typically have a favorable ratio of n-6 to n-3, 2:1 or less. In the US, the ratio is currently about 17:1 due to modern vegetable oils.

DHA, a long-chain n-3 fatty acid, is concentrated in neuronal synapses (the connections between neurons) and is required for the normal functioning of neurons. n-6 fats compete with n-3 fats for space in cellular membranes (which have a fixed amount of total polyunsaturated fat), so a high intake of n-6 fats, particularly linoleic acid, displaces n-3 fatty acids. Lower tissue levels of DHA and total n-3 correlate with measures of hostility in cocaine addicts. Feeding mice a diet high in linoleic acid increases aggressive behavior, and increses the likelihood of rats to kill mice.

If the ratio of n-6 to n-3 in the diet predicts psychiatric problems, we'd expect to see an association with n-3 intake as well. Let's take a look:

This is homicide mortality vs. n-3 intake for 24 countries, published here. The association is significant (p> 0.001) even without correcting for n-6 intake. Of course, one could see this as a cloud of points with a few well-placed outliers. Here are some closer associations from the same paper:

It's clear that both a high n-6 intake and a low n-3 intake correlate with negative psychiatric outcomes. Together, the data are consistent with the hypothesis that the ratio of n-6 to n-3 impacts brain function. Dr. Hibbeln and Dr. Lands do not claim that this ratio is the sole determinant of psychiatric problems, only that it is a factor.

Now to address the big criticism that was brought up by very astute readers of the last post, namely, that the data were purely correlative. Believe me, I wouldn't even have posted on this topic if I didn't have intervention data to back it up. In addition to the animal data I mentioned above, here are more studies that support a causal role of fatty acid balance in psychiatric problems:

• EPA supplementation (a long-chain n-3 fatty acid) reduced aggression and depression in a group of women with borderline personality disorder.
• DHA supplementation improved aggression in young Thai students.
• n-3 supplementation improved symptoms of bipolar disorder.
• EPA supplementation improved symptoms of unipolar depression.
• n-3 supplementation improved perinatal depression.
• n-3 supplementation improved symptoms of major depression.
• DHA and EPA supplementation reduced suicidal behaviors and improved markers of well-being in patients with recurrent self-harm.
• n-3 supplementation decreased anger and anxiety in substance abusers.
  

Most of those were placebo-controlled trials. If we can see a significant effect of n-3 supplementation in short-term trials, imagine how well it would work as a long-term preventive measure.

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Vegetable Oil and Homicide

One of the major dietary changes that has accompanied the downward slide of American health is the replacement of animal fats with industrially processed vegetable oils. Soybean oil, corn oil, cottonseed oil and other industrial creations have replaced milk and meat fat in our diet, while total fat consumption has remained relatively constant. The result is that we're eating a lot more polyunsaturated fat than we were just 30 years ago, most of it linoleic acid (omega-6). Corn oil may taste so bad it inspires you to violence, but its insidiousness goes beyond the flavor. Take a look:


This figure is from a paper that Dr. Joe Hibbeln sent me recently, of which he is the first author. This followed an interesting e-mail conversation with Robert Brown, author of Omega Six: the Devil's Fat. He put me in touch with Dr. Hibbeln and Dr. William Lands (NIH, NIAAA), both of whom warn of the dangers of excessive linoleic acid consumption from modern vegetable oils. Dr. Lands has been researching the relationship between dietary fat and inflammation since the 1970s, and has been a critic of modern vegetable oils for just as long. Both Dr. Hibbeln and Dr. Lands were very generous in sending me a number of their papers. The figure above shows the homicide rate vs. linoleic acid consumption of five countries over the course of 40 years. Each point represents one year in one country. The U.S. has the distinction of being in the upper right.

I asked Dr. Hibbeln how he selected the five countries, and he told me the selection criteria were 1) available homicide and linoleic acid consumption statistics, 2) "first world" countries, and 3) countries representing a diversity of linoleic acid intakes. I'm satisfied that there was probably not a significant selection bias.

What's interesting about the graph is that not only does the homicide rate track with linoleic acid consumption across countries, but it also tracks within countries over time. For example, here is the same graph of the US alone:


And here is the UK, which doesn't suffer as much from the confounding factor of firearm availability:


I don't think we can draw any solid conclusions from this, but it is worth noting that epidemiological associations don't get much better. In the next few posts, I'll explore the data from intervention trials that support the hypothesis that excessive omega-6 consumption, and insufficient omega-3 consumption, cause serious problems for psychiatric and physical health.

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