Thursday, February 18, 2010
Essential Fatty Acids
Why essential fatty acids are important Essential fatty acids, or EFAs, are types of fat that are essential in the diet because they can't be produced by the body. These fats help build cells, regulate the nervous system, strengthen the cardiovascular system, build immunity, and help the body absorb nutrients. EFAs are vital for healthy brain function and vision. There are two families of EFAs: omega-6 (linoleic acid) and omega-3 (alpha-linolenic acid). The body uses these short-chain fats to create long-chain fatty acids, which contribute to health in different ways, depending on their proportion. One of the long-chain fatty acids that the body can make from alpha-linolenic acid is DHA (docosahexaenoic acid), which is critical to brain and eye development. This is why infant formula is fortified with DHA and why pregnant and breastfeeding women are encouraged to have DHA in their diet, either from a food source or a supplement. EPA (eicosapentaenoic acid) is another omega-3 long-chain fatty acid made by the body that's present in breast milk. Like DHA, it's found in fatty fish. Several factors affect the production of DHA by the body, including the amount of omega-6 fat, saturated fat, and trans fat in the diet. An imbalance of omega-6 fats to omega-3 fats can also have a negative effect on immune and inflammatory responses in the body. This is thought to contribute to illnesses such as heart disease and type 2 diabetes. How much does your child need? Ages 1 to 3 years: 7,000 milligrams (mg), or 7.0 grams, per day of omega-6 and 700 mg (0.7 grams) per day of omega-3 Ages 4 to 8 years: 10,000 mg (10 grams) per day of omega-6 and 900 mg (0.9 grams) per day of omega-3 Omega-6 fats are usually plentiful in the diet, and it's likely you only need to focus on making sure your child is getting adequate omega-3s. (Many omega-6 fats come from processed foods that contain oils such as soybean oil.) Your child doesn't have to get the recommended daily amount of essential fatty acids every day. Instead, aim for that amount as an average over the course of a few days or a week. Good sources of essential fatty acids Kids may eat more or less than the amounts of food shown, given their age and appetite. You can estimate the nutrient content accordingly. Good sources of omega-3s include: 1 teaspoon flaxseed oil: 5,700 mg (not recommended for cooking but good for dressings) 1 tablespoon flax seeds, ground: 15,900 mg 1/4 cup English walnuts: 9,100 mg 1 tablespoon peanut butter, fortified with omega-3: 4,950 mg 1 teaspoon walnut oil: 2,380 mg 1 teaspoon wheat germ oil: 3,110 mg 1 teaspoon soybean oil: 2,270 mg 1 teaspoon canola oil: 870 mg 1 tablespoon wheat germ: 500 mg 1 omega-3 fortified egg: 100 mg Most of us get too much omega-6 (primarily from vegetable oils) and not enough omega-3. Choosing fats that are rich in omega-3 for food preparation will ensure your child gets enough. Just a teaspoon of canola oil, for instance, contains the omega-3 most children need in a day. (Note that nuts and seeds are not appropriate for very small children because they pose a choking hazard. For the same reason, nut butters should be thinly spread.) In general, omega-6 fats are more plentiful in the diet than omega-3 fats. In fact, your child will most likely get all the omega-6 fats he needs from processed foods that contain safflower, sunflower, corn, and soybean oils: 1 teaspoon safflower oil: 3,360 mg 1 teaspoon sunflower oil: 2,966 mg 1 teaspoon corn oil: 2,400 mg 1 teaspoon soybean oil: 2,300 mg DHA and EPA: Helping your child get enough While the body uses omega-3s to create DHA and EPA, there are food sources – mostly fish – that will help make sure your child gets enough. The Institute of Medicine's Food and Nutrition Board suggests that a 1- to 3-year-old child could have up to 70 mg of DHA and EPA combined, and a 4- to 8-year-old child could have up to 90 mg of DHA and EPA combined. Encourage your child to eat DHA-rich foods at least once a week. Some good sources of DHA to try: 1 ounce cooked herring: kippered, 334 mg; pickled, 155 mg 1 ounces cooked salmon: 186 to 413 mg, depending on type 1 ounce sardines: Atlantic, canned in oil, drained: 144 mg; Pacific, canned in tomato sauce, drained: 282 mg 1 ounce rainbow trout: wild, 147 mg; farmed, 232 mg; mixed species, 192 mg 1 ounce mackerel, canned: Atlantic, 198 mg; Jack, 226 mg 1 ounce barramundi: 174 mg 1 ounce pollock: Atlantic, 128 mg; walleye, 80 mg 1 DHA-fortified egg: about 100 to 150 mg (depending on the brand) Can your child get too much essential fatty acids? Yes, your child can get too much of either of the essential fatty acids, which can then cause an imbalance. It's best to get the right balance of fats by choosing mostly fats rich in omega-3 and by avoiding trans fats and saturated fats. Trans fats – often called "partially hydrogenated oils" on the label – are found in many fried foods (like French fries), baked goods (like cookies, pastries, pizza dough), and stick margarines and shortenings. Trans fats raise LDL ("bad") cholesterol and lower HDL ("good") cholesterol and increase the risk of developing heart disease, stroke, and type 2 diabetes. Saturated fats come mostly from animal sources like meat and dairy – fatty meats and lard, and cream, butter, and cheese. They're also found in baked and fried foods and some plant foods, like palm oil, palm kernel oil, and coconut oil.
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