Thursday, January 14, 2010
Fat is probably one of the most controversial topics in the nutritional field, and for good reason. Consuming the correct amount of fat can be like walking a tight rope. Fats provide energy and are vital for building and maintaining cell membranes and producing important hormones. They slow down the body’s absorption of nutrients so that we can go longer without feeling hungry. They are also carriers for the fat-soluble vitamins A, D, E and K. We need to eat fat to be healthy. But too much fat can lead to a variety of well-known health complications such as heart disease and diabetes, and can make you, well, fat. The problem of fat consumption is complicated in by the food industry, which continually promotes “low-fat” and “fat-free” versions of foods that naturally contain fats, such as dairy products and snack foods. In our entertainment industry, we are bombarded by images of emaciated models, portraying to us that thinner is better. Finally, in our own reality, there are more overweight and obese people than ever.
It’s no wonder that we can’t make sense of fat. In this article, I will provide a summary of different kinds of fatty acids, paying particular attention to the subject of omega-3 fatty acids, to help answer Stuart’s question, and hopefully provide some insight for the rest of us who may share similar concerns.
Before we discuss omega-3 fatty acids, we need to take a step back and review our basic knowledge of fat in general. Sally Fallon, author of Nourishing Traditions, all fats and oils are combinations of saturated fatty acids, monounsaturated fatty acids, and polyunsaturated fatty acids. We can classify fats by the amount of each acid they contain and the length of their chain.
Below are descriptions of each type of fatty acid:
Saturated fatty acids: These fats are generally solid at room temperature and include animal fats, dairy products, and tropical oils. Although they have a bad reputation for elevating bad cholesterol and causing heart disease and other cancers, other studies have proven that saturated fats can protect us from viruses, yeasts, and harmful bacteria. Some studies also show that these fats are less likely to cause weight gain than olive oil or other commercially produced oils.
Monounsaturated fatty acids: These fats are generally liquid at room temperature and solid at semi-solid under refrigeration. Sources include olives, olive oil, canola oil, avocados, most nuts (except walnuts), sunflower oil, and safflower oil. They can protect against heart disease, reduce blood pressure, and enhance blood flow, can help regulate blood pressure, and may slightly increase HDL “good cholesterol.”
Polyunsaturated fatty acids: are liquid at room temperature and under refrigeration. Sources include most vegetable oils, seeds, nuts, grains, legumes, other plant foods, and many commercially processed oils. Studies regarding the health benefits of polyunsaturated fatty acids are somewhat inconsistent. Some studies show these fatty acids to protect our health, while others reveal they can lead to increased risk for types of cancer, heart disease, immune system dysfunctions, high blood pressure, damage to the liver, reproductive organs, and lungs, digestive disorders, learning disabilities, impaired bodily growth, and weight gain.
Essential fatty acids: are polyunsaturated fatty acids that include omega-6 and omega-3 fatty acids. Both are essential for maintaining good health; however, maintaining a healthy ratio of omega-6 acids to omega-3 acids is also extremely important. Omega-3 fatty acids are necessary for cell oxidation, metabolizing certain amino acids, producing important nervous system hormones. Good sources of omega-3 fatty acids include flaxseeds, flaxseed oil, olive oil, seaweed, algae, eggs, and fish.
You may have heard of the omega-6 and omega-3 fatty acids before and have wondered why they are so important, and so confusing. Before the food industry started making refined vegetable oils, people consumed these fatty acids in roughly equal amounts. However, most commercial vegetable oils that we find now in the grocery store are comprised of up to 75% omega-6 acids and very often 0 or 1% omega-3 acids. Although omega-3 acids can be found in eggs and fish, the commercial food industry has upset this balance as well: eggs from grain-fed chickens contain little to no omega-3 fatty acids.
There’s one more complication: some polyunsaturated fats that contain omega-3 fatty acids can become oxidized or rancid when heated and can cause more harm than good. This can cause damage to cell membranes and red blood cells, which can ultimately cause free radical damage that can range from wrinkles and premature aging to plaque buildup in arteries to tumors and autoimmune diseases.
So what to do? From my research on omega-3 and omega-6 fatty acids, I’ve gained two main insights: we need to be mindful of our consumption of these fatty acids (in general limiting omega-6 and boosting omega-3 intake), and we need to be aware of which oils can be harmfully denatured when subject to high temperatures.
First objective: how can we consume more omega-3 fatty acids? Omega-3 fatty acids can be divided into three different categories:
LNA (Alpha-linolenic acid): can be found in flaxseed (and flaxseed oil), hempseed, walnuts (and walnut oil), soy (and soybean oil), and olive oil.
EPA (Eicosapentaenoic acid): can be found in fish, seaweed, and microalgae (such as seaweed).
DHA (Docosahexaenoic acid): can be found in fish, eggs, and microalgae.
Getting enough EPA and DHA has long been a concern for vegetarians, and especially vegans because of their presence largely in fish and eggs. For vegans, it’s important to note that fish get their EPA and DHA content from eating microalgae, so vegans can take a microalgae supplement to obtain these fatty acids. EPA can also be obtained by eating seaweed, an important staple in Asian diets. For all of us, eating more of the foods above that contain omega-3s is probably a good idea. This probably means buying wild caught fish instead of farmed and organic eggs instead of conventional, as the food industry’s cultivation methods have largely decreased if not eliminated omega-3 content in these foods.
Second objective: how to ingest LNAs without oxidizing them or letting them become rancid. One easy way to get LNAs is to sneak ground flaxseed into your meals. I sprinkle ground flaxseeds on to my oatmeal in the morning, mix it into peanut butter, or add it to baked goods. This also gives you an extra dose of fiber. Always use ground flaxseeds instead of whole, because this is the only way your body can digest and absorb the nutrients found in flaxseeds. Keep ground flaxseeds in an opaque, airtight container in the refrigerator to prevent them from becoming rancid.
If you prefer to use the oil, consume LNA-containing oils in salad dressings and dips or add them into sauces or soups late in the cooking process. Olive oil can be used for cooking at very low or moderate heats; flaxseed oil should never be used for cooking.
There is so much more information about omega-3 and omega-6 acids, but for the sake of simplicity and ease of reading, I’ll stop here and recommend some good resources I’ve found in the process of researching this topic.
Nourishing Traditions by Sally Fallon
Becoming Vegan by Brenda Davis and Vesanto Melina
The Omnivore’s Dilemma and In Defense of Food by Michael Pollan
Eat More, Weigh Less by Dr. Dean Ornish
Websites with helpful articles:
The Vegetarian Society
Women to Women
I’d love to hear your thoughts, comments, and concerns about this issue. I am by no means an expert nutritionist or dietician, so please feel free to share!
Posted by Emily Rex at 9:46 PM