Omega-3 is a high-profile nutritional trend, ranking alongside with calcium and fiber in consumers' concerns [source: Watson]. And unlike some food fads that are over in a flash, the need for omega-3 may be as genuine as advertised.
Omega-3 refers to omega-3 fatty acids. Fatty acids are the building blocks of fats, which, despite their misunderstood reputation, are vital nutrients. Omega-3 is used to regulate blood clotting, build cell membranes and support cell health. It's polyunsaturated, which is the relatively heart-healthy kind of fats that help reduce blood triglycerides (fats) and low-density lipoprotein (LDL), the so-called bad cholesterol.
Omega-3 also curbs inflammation. While inflammation is a normal part of the body's immune response, research indicates that it also underlies a host of serious illnesses, including cardiovascular diseases, cancers and autoimmune diseases.
Omega-3 is called an essential fatty acid: It's essential to health, and because the human body doesn't produce it, it's essential in the diet. Unfortunately, the typical American diet includes relatively few foods that are rich in omega-3.
Complicating matters is another essential fatty acid, omega-6. Omega-6 is another polyunsaturated fatty acid, and it complements the functions of omega-3 in foods. In a contrasting role, however, omega-6 promotes inflammation. What's more, omega-6 may compete with omega-3 for metabolization in the body. The modern Western diet tends to be top-heavy with omega-6 acids, largely due to the reliance on refined vegetable oils both in homes and in the food industry.
In this article, we'll fill your plate with 10 foods that can help even the score between omega-6 and omega-3 fatty acids. We'll highlight proteins, dairy products, veggies and snacks, and fill your knowledge stores with some basic science to help you identify other good choices.
Starting with pasture-raised animals lets us explain how omega-3 acids enter the food chain. It also shows how tweaking conventional production methods can affect nutrition in the food supply.
The omega-3 acids in most plants are alpha-linolenic acids (ALAs). ALAs have short chains of carbon. Humans and animals convert them into two long-chain forms that are usable by their bodies: eicosapentaenoic acids (EPAs) and docosahexaenoic acids (DHAs). The process isn't terribly efficient, however: Only about 5 percent of the ALA is converted. Thus, foods from animals -- in which the ALA has already been converted into usable forms -- are generally more efficient sources of omega-3 than foods from plants.
Conventionally raised meat is fed corn. Corn oil is among those mentioned on the last page as being high in omega-6 acids, and the same holds true for the corn kernels. Pasture-raised animals subsist largely on grasses, which not only lowers their omega-6 levels but also boosts their levels of omega-3. In one test involving cattle, the ratio of omega-6 to omega-3 dropped from almost 9:1 in corn-fed to under 2:1 in grass-fed animals. In another experiment, the numbers dropped from more than 13:1 to less than 3:1 [source: Daley, et al]. Goats, sheep and bison have all shown similar results. Poultry scientists are working to achieve the same results with chicken and other birds.
Studies have also shown that grass-based diets for beef cattle lower the levels of two saturated fatty acids, myristic and palmitic, in their meat. These fatty acids tend to increase blood cholesterol levels in people who consume them [source: Daley, et al].
Like beef cattle, cows (and goats and sheep) that are grass-fed produce milk with higher amounts of omega-3. More accurately, these animals are forage-fed, a term that also includes legumes and other non-grain feedstuffs. Also like beef cattle, the levels of fatty acids will vary with the breed of animal, the type of grass they eat, where they're raised and the time of year the milk was produced. For example, animals that are raised in colder climates where grass isn't available year-round might be given soy meal or silage, such as corn stalks and cereal grasses, during the winter. Animals fed such mixed diets produce milk with higher ratios of omega-6 to omega-3 acids. The less grass they're fed, the higher the ratio [source: Clancy].
One factor that can't be quantified is pasture management. Graziers (farmers who graze their livestock) need to know how to keep pastures healthy to supply their herd's needs. New findings are adding to their store of knowledge and guiding management practices.
As with meat and dairy foods, eggs are enriched by adding types of feed that are high in omega-3 fatty acids to the hen's diet. Enrichment can drop the ratio of omega-6 to omega-3 acids from the 15:1 found in conventional eggs to as low as 1:1 [sources: Rose Acre Farms; NutritionData].
While some pastured-raised hens obtain omega-3 by foraging on bugs and seed, many egg farmers control the process by feeding their hens flaxseed, fish oil or meal, and algae. Flax is rich in ALA. Fish byproducts have DHA, one of the forms of omega-3 that the human body synthesizes from ALA. Algae are among the few plants that also provide DHA. If you're thinking of buying omega-3 enriched eggs, check the company's Web site to see whether it specifies the source of the fatty acids or the amount of each form.
The omega-3 acids in eggs are concentrated in the yolk, as are the other fats and cholesterol. People who avoid egg yolks on that account will be heartened to know that some omega-3 enriched eggs are also lower in saturated fat and cholesterol than conventional eggs. Again, you may need to do some research to learn each brand's particular fat and cholesterol values.
Many common soy foods are good sources of omega-3 fatty acids. However, their high content of omega-6 acids hurts their profile for heart health and disease prevention.
Edamame is a notable exception. Edamame are green soybeans (not to be confused with the mature seeds). You can buy them roasted and ready for snacking, or partially cooked for use in salads, stir-fries and other recipes. Their omega-6 to omega-3 ratio of 5:1 is a little on the high side [source: NutritionData]; we are striving for balance, remember. However, they also contain isoflavones. Isoflavones are plant estrogens that seem to lower blood cholesterol in general and LDL (the "bad") cholesterol in particular.
Edamame have other nutritional benefits as well. Like many other soy foods, they're good sources of quality protein. As whole legumes, they also provide fiber. Plus, they're one of the few snack foods that made our list -- in case reading this article makes you hungry.
Wild rice's inclusion on this list should come as no surprise -- because it's not a rice, but a grass. (For that matter, it's not always wild. Most so-called wild rice in North America is grown on farms.) As you may have predicted from our previous discussions on pasture-raised meat and dairy foods, being a grass makes it a likely candidate for high omega-3 content. Wild rice is not only a good source of omega-3, but contains only slightly more omega-6, for a ratio of about 1.25:1 [source: NutritionData].
White and brown rice, on the other hand, are grains. Grains offer nutritional benefits of their own. But again, grain-based feeds are responsible for the high levels of omega-6 acids found in conventionally produced foods from animals, so make sure you're buying wild rice if you've got omega-3 in mind.
All of the nut varieties consumed commonly in the United States -- including pecans, pistachios and almonds -- contain polyunsaturated fats. But walnuts stand out for their significant amounts of omega-3, which is also well-balanced with omega-6. Like other plant-derived foods, their omega-3 is in the form of ALA.
Besides munching on walnuts as a snack, you can use them to replace less healthful ingredients in recipes. In cookies, for example, swapping semi-sweet chocolate chips for the same amount of walnuts will reduce saturated fats by 50 percent and sugars by 95 percent, while boosting protein and adding trace minerals such as magnesium, manganese and phosphorus.
Likewise with walnut oil. Stir-frying your veggies in walnut oil instead of olive oil increases omega-3 acids tenfold while cutting the ratio to omega-6 in half.
The canola plant is a modified variety of rapeseed. When Canadian farmers began growing the crop in the 1980s, it was as a biodiesel fuel. It was valued for being low in saturated fats, which gave it excellent flow properties in cold weather. Today canola is also recognized for its exemplary heart-healthy profile. It has the highest amount of omega-3 fatty acids and the best omega-6 to omega-3 ratio, about 2.5:1, of all common culinary oils [source: Canola Council of Canada; NutritionData]. It's also combined with corn or soybean oil to improve the omega content in blended products.
Canola oil's versatility helped it make our list. Culinary oils each have their own smoke point -- a temperature range where they start to degrade, or break down. Degraded oils impart an unpleasant taste and shorten the shelf life of foods they're used in. They may also be harmful to your health [source: Foster].
Most unsaturated fats have a relatively low smoke point. However, the canola used for oil is specifically bred to have a high smoke point, around 435 degrees Fahrenheit (223 degrees Celsius), meaning you can use it for frying and baking as well as drizzling over your salad.
Flax is something of a mystery food to most Americans; it's probably best known as an ingredient in breakfast cereal. Yet it's a powerhouse of omega-3 that's definitely worthy of inclusion in our top 10.
Flax can be purchased in seed form and in oil form. In each, about 70 percent of all its fats are polyunsaturated, and close to 60 percent of its fats are omega-3. The seeds provide fiber, protein and high levels of lignans. Lignans are plant estrogens -- like the isoflavones found in edamame -- that actually seem to help prevent the growth of cancerous tumors. Whole seeds are a healthful snack. They add crunch and a nutty flavor to salads, smoothies and baked goods.
Flax seed oil is the best plant source of ALA, and it's the only culinary oil to win out over canola in omega-6 to omega-3 ratio. Flax oil is actually lopsided with omega-3, with a ratio of 1:3.5. However, it has a low smoke point, about 225 degrees Fahrenheit (107 degrees Celsius). Thus, it's best used in fresh recipes such as salad dressings or pesto.
Another overlooked seed source of omega-3 worth mentioning here is chia. Yes, the same seed that sprouts on novelty gifts also has heart-protective properties.
It may surprise some people to see beans on this list. Beans are touted for being low in fat, after all, and so they are. A half-cup (125-milliliter) serving has only 0.5 grams of fat, and most of those fats are polyunsaturated. A caveat, however: Most of those are omega-6. Remember, omega-6 acids are essential for good health, but they're already abundant in the food supply. In the quest for balance, we can recommend several common varieties of beans. Black beans, for example, are almost equal in omega-6 and omega-3 [source: NutritionData]. Kidney beans score even higher, with about 50 percent more omega-3 than omega-6 [source: NutritionData].
It's good thing for human nutrition that some fish live in cold waters. Some of the fats in coldwater fish consist of long, kinked carbon chains, which fill up space to add insulation. These are high-quality omega-3 acids, the EPA and DHA that are essential to human life. Atlantic salmon, bluefin tuna, Atlantic mackerel and anchovies are especially good sources.
This bounty comes with strings attached. First is the question of sustainability. The bluefin tuna population, for example, is being depleted by overfishing. This fish may be caught in ways that endanger sea turtles, birds and other wildlife. Fish farms, on the other hand, can release contaminants into local waters. And if they escape, the farm fish can threaten native wild species.
Food safety is another issue. Some very good wild-caught sources of omega-3 are at the top of the food chain. Any toxins in the fish they eat can accumulate in their flesh. Mercury poisoning is one well-documented example.
Eating fish, whether for omega-3 or any reason, proves the wisdom in knowing where your food comes from. Educating yourself on your food supply and its impact on the environment is an investment of time and effort. The payoff is a healthier life for you and for the planet.
HowStuffWorks explores whether posting calories on the menu helps consumers make better food choices.
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