Are you getting enough fat in your diet? Just a few years ago, the question would have sounded crazy, but many scientists and nutrition experts now believe that mono- and polyunsaturated fats have a critical role in any healthy eating plan. These versatile fats seem to offer a variety of benefits for the cardiovascular system; likewise, they fight an impressive range of diseases.
Fish, not defibrillators
Each year, about a quarter of a million people in the United States with no prior history of cardiovascular disease die of sudden cardiac death, which occurs when the heart starts beating uncontrollably. To combat this situation, health officials are encouraging people to learn how to use defibrillators, which shock the heart back to steady pace. But one study discovered that even if every home and public place (such as airports and restaurants) in a community had defibrillators, only about 1%of sudden heart attacks would be prevented.
In comparison, increasing blood levels of omega-3 fatty acids within a population would ward off nine times as many deaths, according to a study in the American Journal of Prevention Medicine. To get the right level of protection, people would need to take fish-oil supplements, the authors of this study say. Nevertheless, one study of 19,000 men found that simply consuming fish a couple times a week cuts the risk of sudden cardiac death in half. Another study found that eating fish just once or a couple of times per month provides similar protection against strokes. The American Heart Association recommends eating several servings of fish each week.
It’s not just the polyunsaturated fat in fish that protects the cardiovascular system. The good fats in nuts, most of which contain a healthy dose of both kinds of unsaturated fat (mono and poly), also offer this benefit. Eating three serving of almonds, peanuts, pecans, or walnuts per week as part of an overall heart-healthy diet may decrease total cholesterol by up to 16 percent and LDL (“bad”) cholesterol by up to 19 percent, according to a study published in the Journal of Nutrition. The fat in vegetable oil helps lower cholesterol, too.
Add oil, hold the sugar
Eating more nuts, olive oil, and other foods rich in monounsaturated fats may also help safeguard you from the threat of type 2 diabetes. For starters, filling up on these good fats means you’ll have less room for fatty meat, whole milk, and other sources of saturated fat, which contributes to insulin resistance—and high blood sugar. Left unchecked, chronically elevated blood sugar can cause type 2 diabetes—yet another reason why trimming the saturated fat from your meals is a no-brainer.
Exchanging saturated fat for monounsaturated fat may be even better than exchanging it for carbs. This theory remains somewhat controversial, but research shows that diets high in monounsaturated fat control blood sugar just as effectively as the typical high-carb, low-fat diet many doctors recommend to prevent and control diabetes. In fact, some studies have shown them to be superior.
What’s more, increasing your intake of monounsaturated fat appears to have other benefits you don’t get from a high-carb diet, such as lowering levels of triglycerides. A study by Mexican researchers found that diabetes patients were able to lower their blood sugar while eating diets rich in olive oil and avocados. The study found that switching over to a high-carb diet worked, too. However, the patient’s triglyceride levels dropped 20 percent while eating the high mono diet, compared to just 7 percent when they followed the high-carb meal plan.
Fighting cancer, Mediterranean style
The Lyon Diet Heart Study grabbed headlines mostly for the apparent cardiovascular benefits of the Mediterranean-style diet. But here’s more good news: Those same study subjects, who ate plenty of fish and olive oil, cut their risk of cancer by 61 percent.
Although many questions remain about the link between diet and cancer, intriguing evidence suggests that healthy fats may protect against some form of the disease. For example studies in the 1990s showed that women who consumed plenty of olive oil lower their risk of breast cancer by about 25 percent. More recently, a team of researchers at Northwestern University in Chicago discovered that oleic acid, the main form monounsaturated fat in olive oil, reduces activity of a gene that causes an aggressive form of breast cancer by 46 percent. What’s more, oleic acid appears to increase the effectiveness of transluzumab (Herceptin), a drug used to treat breast cancer. A second study found that fish oil may offer similar effect.
Salmon, the edible antidepressant
If you ever travel to Iceland in the middle of January, don’t count on seeing much of the sun: It rises at about 10 a.m. and disappears by 5 p.m. However, don’t expect to find a bunch of gloomy natives, wither. Icelanders have surprisingly low rates of seasonal affective disorder, the mood condition caused by low exposure to sunlight. Their secret to happiness? Some scientists think its fish oil.
Consider this: The typical Icelander eats five times more seafood than do people in the United States or Canada. Several other studies have shown the rates of depression tend to be lower in countries where fish is frequently the main course. What’s more, University of Pittsburgh researchers recently found that people who had the highest levels of omega-3 fatty acids in their blood were 53 percent less likely to report feeling mildly or moderately depressed.
No one is certain why fish oil may help fish the blues, although DHA may affect the formation of chemicals linked to depression. While there’s no guarantee that eating more salmon and tuna will make you happy-go-lucky, some scientists are studying whether having low levels of omega-3s contributes to depression. One scientific trial found that people with bipolar depression who added fish-oil supplements to their medication regimen had milder symptoms and fewer relapses than similar patients given placebo supplements.
Feed your memories well
Think of fish oil as brain food. The body uses is DHA to build and repair the membranes that protect brain cells. DHA also seems to be necessary for brain cells to communicate with one another. Eating plenty of fish may even lower your risk of dementia, the gradual loss of mental ability that sometimes accompanies aging. For example, researchers at Chicago’s Rush-Presbyterian-St. Luke’s Medical Center found that people who ate fish just once a week reduced their risk of Alzheimer’s disease by 60 percent. The same research group also found that diets high in saturated fat and trans fat (the kind in hydrogenated cooking oil used by restaurants and food processors) seem to increase the risk of dementia. “What appears to be healthy for preventing cardiovascular disease also appears to be helpful for preventing Alzheimer’s disease,” says lead scientist Martha Clare Morris, Ph.D.
Scientists have also linked a deficiency of omega-3s to other cognitive problems, including attention deficit hyperactivity disorder (ADHD). Blood tests show that children who struggle with the impulsivity, tantrums, and learning difficulties associated with this condition tend to have unusually low levels of DHA. Preliminary research hints that correcting that deficiency may help kids with ADHD settle down and focus. For example, one study by researchers at McLean Hospital near Boston showed that dietary supplements containing salmon oil and other fatty acids (as well as vitamins and plant nutrients) controlled ADHD symptoms as well as Ritalin, the widely prescribed stimulant drug.