Many of us could do with a major rethink of our daily dietary fat intake. For some, this will mean cutting back while, for others, it means reorganising our diets to eat more or different types of fats. Here are a few pointers that should help:
* Trans fatty acids are the only truly bad fats. Although we now assume that polyunsaturated fats are heart-protective, this has not been satisfactorily proven. Only trans fatty acids - the 'fake', man-made hydrogenated oils, not the saturates that occur naturally in animal flesh, nuts and dairy products - have been consistently proven to cause atherosclerosis, coronary heart disease, cancer and other health problems (Lancet, 1994; 343: 168-71).
* Variety is the key. Your best health insurance policy is to get dietary fats from a wide variety of sources. Before gulping down supplements, consider how you might incorporate more natural fats into your diet.
* Do it yourself. Humans may be able to manufacture the omega-3 eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from red and brown algae in much the same way that fish do (J Nutr, 1996; 126: 3032-9) - but only if the body is optimally nourished. The ability to convert alpha-linolenic acid (LNA) to EPA can be hampered by low levels of vitamins B3, B6 and C, magnesium and zinc. Also, an overbalance of saturated fat, trans fatty acids and cholesterol can interfere with conversion. If you want to obtain omega-3s from food, you must eat an excellent diet and have adequate levels of these other nutrients.
* Organic is best. Many industrial pollutants are lipophilic - they are attracted to fat. This means that animal fats, dairy products, seed and fish oils may be substantially polluted with toxins like pesticides, dioxins, polychlorinated biphenyls (PCBs) and xenoestrogens. To get the best out of whatever fats you eat, choose organic wherever possible.
* Sensible supplementing. If you're worried about high-dose supplementing, a good compromise is to take half your requirements from food and half from supplements - 500 mg a day each. Weekly doses of 1500 mg have also been recommended. But bear in mind that fish-oil supplementation can lower blood concentrations of vitamin E and other fat-soluble nutrients such as retinol and beta-carotene (Lipids, 1992; 27: 533-8; Am J Clin Nutr, 2000; 71 [Suppl]: 197S- 201S), so you will need to add an extra 200 mg of vitamin E to your regime.
Fish oils should be approached with caution by diabetics as they may worsen glucose control (J Diabetes Compl, 1996; 10: 280-7). Adding garlic or pectin to your daily supplement programme appears to mitigate this.
* Avoid drowning in omega-6 and worsening your omega-6 to omega-3 ratio. Consider cutting down on (or avoiding altogether if you take high-dose supplements of evening primrose oil) vegetable oils, spreads and shortenings that contain sunflower, corn, soy, safflower and canola oils. Hempseed oil also contains a relatively high omega-6 to omega-3 ratio so, if your diet is already high in omega-6, this could push the balance off even further.
Better substitutes for cooking are high-quality, low-processed, extra virgin olive oil, coconut or palm oil, avocado oil or organic (better still, grass-fed organic) butter.
* Look to dietary sources of omega-3 and not simply supplements. It may be possible to get all of the omega-3 fatty acids from our diet. Try eating two portions of oil-rich fish (salmon, mackerel, herring, sardines, albacore tuna and black cod, or sablefish) a week. This will provide around 2-3 g of very-long-chain fatty acids - the amount found in three or four 1000-mg fish-oil capsules. Organically reared grass-fed animals, eggs from grain-fed chickens and wild game will also provide useful amounts of this and other naturally occurring fats.