Bad News About Omega Fatty Acids
By Cassandra Forsythe-Pribanic, PhD, RD, CSCS
To many people, “fat” is one of those three-letter words that instills fear of heart disease, obesity, and a lifetime of bad hair days (I’m kidding about that last one… sort of). But one type of fat that has joined the popular crowd of nutrients such as amino acids and dietary fiber, is essential fatty acids.
Essential fatty acids (EFAs), have steadily become the new buzz word in nutrition for several important reasons. The biggest reason is its prefix, “essential." Yes, fats in this category are something your body cannot make, but needs for survival and to prevent deficiencies. This is in contrast to many other nutrients that your body can actually synthesize, like carbohydrates and some proteins. As such, EFAs must be obtained by eating certain foods and taking dietary supplements regularly. You can think of them like water or calories; without either of these, your body will not function properly and will eventually suffer ill fates.
But what is it about EFAs that makes them so, well, essential? And, what happens without them? Finally, how can we get them in our diets and what are their benefits? Continue reading to learn everything you need to know about this special class of nutrients.
All About Essential Fatty Acids
EFAs fall within the category of dietary fat. In foods, fat is actually a structure made up of several different types of fatty acids attached to a compound called glycerol. This whole unit together is known as a triglyceride, pictured below:
A triglyceride basically looks like the capital letter “E,” and each arm of the “E” is a fatty acid. These fatty acid “arms” are chains of carbon molecules linked together in varying lengths, and with different amounts of attachments (or bonds) between each carbon. Chains with only single attachments are known as saturated fatty acids (SFAs), those with one double attachment are known as monounsaturated fatty acids (MUFAs), and those with two to six double attachments are called polyunsaturated fatty acids (PUFAs).
EFAs are a type of PUFA; they have one or more double bonds, and they‘re further categorized into one of two classes: Omega-6 or Omega-3. The omega-6s are named because their first double bond is six carbons from one end, where omega-3s have their first double attachment three carbons away.
The essentiality of two of these omega fats, linoleic acid (LA, an omega-6), and alpha-linolenic acid (ALA, an omega-3) is because humans, and all vertebrates for that matter, do not have the enzymes to make them from other fats in the diet. Plants, however, do have these special enzymes and are one of the main dietary sources for us. Humans can also get them from eating animals that have consumed these plants, and have now accumulated them in their body fat stores.
As you can see from the table above, there are many ways to get omega-6 EFAs into your diet. However, obtaining omega-3s is a bit more difficult. To make matters worse, consuming too few omega-3s compared to omega-6s has been associated with higher rates of inflammatory diseases like heart disease, diabetes, arthritis, cancer, and inflammatory bowel disease. It has been suggested by some experts that humans should ideally consume no more than a 6:1 ratio of omega-6 to omega-3 fatty acids, with lower levels recommended for certain conditions.
Finding The Right Omega Balance
Starting in the 1900s, the North American dietary fat consumption drastically changed. With new industrial processes and a greater demand for food to feed a rapidly growing population, we shifted from eating fats in their natural state to those in packages and pre-prepared forms. We also became highly scared of saturated fats, like those in butter and tropical oils, and so turned to margarines and refined vegetable oils.
Fatty fish also became less popular because we thought fat was deadly, so we chose less-nutritious white fishes and low-fat versions of poultry and meat (and, of course, we had to cover them in breading and high-sugar sauces). Finally, because we were eating so much beef and chicken, these animals had to be fed grain-based diets instead of naturally grazing on grass - there was not just enough pasture to keep up.
All of these food changes has lead our current population to have a diet heavily based on omega-6 fats, with very few omega-3s. The margarines, fish, beef, pork, and poultry we eat now are all dominant in omega-6 linoleic acid (LA). In turn, our dietary ratio of omega-6 to 3s is much different than our healthier ancestors: it has been estimated that we currently eat an omega-6 to omega-3 ratio of 15-20:1, compared to 1:1 many years ago (when heart disease was not the #1 killer at such young ages).
During evolution, omega-3 fatty acids were found in most all foods consumed: meat, wild plants, eggs, fish, nuts, and berries. But now the picture has changed and our health has suffered. True, other factors come into play, like lack of physical activity and excessive sugar intake, but dietary fat imbalance plays an important role.
The problem with excessive omega-6 fats is that in the body are many:
• Omega-6 LA competes with the normal metabolism of omega-3 ALA to EPA and DHA, so that much less can be made in the body through the normal omega-3 pathway.
• Omega-6s drastically reduce incorporation of omega-3 EPA and DHA into cell membranes when they are consumed in the diet (normally, EPA and DHA would be placed into membranes).
• Omega-6 fats in the body are highly susceptible to free-radical attack and produce compounds such as oxidized LDL cholesterol which contribute to atherosclerosis.
• When consumed as part of a normal diet, omega-6 (LA) is converted to pro-inflammatory products (prostaglandins, thromboxanes, leukotrienes) which contribute to plaque formation on arteries, allergic responses, increased blood pressure, and tumor growth. Omega-3s have the opposite effect:
Basically, many current common diseases can be linked back to excess omega-6s in our food supply, which leads to chronic inflammation. The solution then is to reduce our intake of these fats and increase our intake of omega-3s. But remember: a balance is important and some omega-6s are still essential.
What Is The Ideal Omega-6 To Omega-3 Ratio?
In today’s society, it’s practically impossible to get a 1:1 ratio of omega-6s to 3s as we did in the past. Also, EFA experts do not recommend we strive for this since we have more of a requirement for omega-6s than we do 3s, and not all omega-6s are bad. Thus, for disease prevention and optimal body processes, a 6:1 ratio, or somewhat less, is ideal. Therefore, in a typical diet containing about 60 grams of total fat and 20 grams of PUFA, you’d aim for at least 4 grams of omega-3s, which you can easily get from food and supplements.
Making Omega-3 Fatty Acids
When people consume LA or ALA, these fatty acids can be converted to other important omega-6 and omega-3s in the body, but this doesn’t always occur effectively. Omega-6 LA is often easily transformed to omega-6s known as gamma-linoleic acid (GLA) and arachidonic acid (AA). GLA is considered a good fat to have in our bodies, but AA is mostly not – it depends on the situation you’re looking at though.
The most important conversion process for our health and well-being is the creation of special omega-3 fats known as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) from ALA. High levels of EPA and DHA in our cells is very beneficial for lowering our risk of diseases, preventing cancer, avoiding depression, and correcting attention deficit disorders. Also, DHA is very important for visual acuity and development of the brain. Unfortunately, for most humans, the conversion of ALA to EPA and DHA is not an efficient process. It has been estimated that only 5-10% of ALA is converted to EPA and 2-5% is converted to DHA; considering how little ALA is in the diet to begin with, this is barely anything at all. Part of the reason minimal ALA is converted to EPA and DHA is that the body prefers to burn it as a fuel – studies with humans have shown that as much as 34% ALA is breathed off as CO2 (via metabolism). Thus, for optimal intake of EPA and DHA, we should aim to eat these food sources regularly instead on relying on our body to make them for us:
Significant Sources of EPA and DHA
• Cold water fatty fish (salmon, trout, sardine, mackerel, herring)
• Shellfish (shrimp, mussels)
• Marine algae
And technically, since EPA and DHA can be made in the body from ALA, they’re not essential. But since we are very limited in what we are able to synthesize, and these fats are an important part of healthy cell membrane functioning, they are crucial for everyone.
How Do We Know EFAs Are So Essential?
If either LA or ALA are missing in the diet because a person chooses to eat a fat-free diet, or they select fats that are low in one or the other, the health of body cells deteriorates, and deficiency symptoms develop. Historically, rats that were fed fat-free diets failed to reproduce, grow normally, or remain healthy. At first, these issues were thought to be due to Vitamin E deficiency (a fat-soluble vitamin), but was then discovered to be due to a lack of omega-6 fat. In humans, signs of omega-6 LA deficiency include dermatitis, poor wound healing, loss of hair, and infertility. Thankfully, all of these outcomes are reversible.
No distinct disease occurs in humans when omega-3 ALA is missing in the diet, but as mentioned, these fatty acids are required for proper vision and central nervous system development and functioning. They also compete with pro-inflammatory products of omega-6 mediators in the body and produce an anti-inflammatory state in the body. Finally, people who consume plentiful omega-3s from seafood and flax have been observed to have reductions in body fat and increases in the ability to use carbohydrate as a fuel (improved insulin sensitivity); we’ll explore more of these benefits in Part II.
Overall, omega-3s are fats that everyone should include in their diets right now; they’re one fat you shouldn’t be afraid of, but rather, should seek out for optimal health.
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