The less fat you eat, the better – right? Not necessarily. Dietary fats were once considered an evil, but we now have a better understanding of them – the ‘good’ and ‘bad’ – and the benefits of balance.
Half a century ago, scientists mad discovery that made us think hard, almost for the first time, about our food and health. People who live in countries where the average diet is rich in saturated fat have far more heart attacks than people who eat less red meat, dairy foods and other sources of saturated fat. Later research showed that eating saturated fat raises blood levels of cholesterol, causing this waxy substance to build up in the arteries and block blood flow to the heart.
At the time, we already knew that fat provides twice as many kilojoules as sugar, and is stored in the body much more readily than other fuels. Many research studies had already shown that fat is less filling than protein or carbohydrates as people tend to consume a similar volume of food irrespective of its composition, which means they will overeat if the food is high in energy-dense fat.
So it seemed logical that, with an increasing incidence of obesity, reducing fat intake was suggested as the solution. Low-fat high fibre diets such as the Pritikin Diet and the F-Plan became popular. Cook-books loaded with fat free recipes filled bookshops. ‘Non-fat !’ and ‘Fat-free!’ were stamped on food labels, and often on products that never contained fat in the first place.
These messages may have convinced you to make some positive and important changes, such as switching from full-fat milk to skim and removing bacon from your diet, but they also led consumers to make some unfortunate choices. One consequence of the anti-fat movement was that many people cut back on all fats – a trend that, ironically, may have actually made us sicker in the long run, according to some prominent medical experts.
Firstly, many of the new low-fat food products were still very energy-dense, because the fat had been replaced with high-kilojoule sugar syrups and highly processed starches. These ingredients do not have any nutritional advantages over the fats they replaced, and in some cases have been associated with health problems of their own. Secondly, we do need some fat in our diets, for good health.
Your body stores about 80 percent of the fat you consume. Ideally, you burn off most of this reserved energy by staying physically active. If not, the fat you eat becomes the fat that makes your clothes too tight and endangers your health. However, about 20 percent of the fat in your diet is not stored. Instead, your body puts it to work, since an astonishing variety of tissues and biological processes require a daily infusion of fat. Without fat, your hair and skin would be dull and dry. And more importantly, dietary fats allows your body to absorb the fat-soluble vitamins, A, D, E and K. every cell in your body needs fat to build a healthy protective membrane. Fat also provides the raw materials that your body uses to produce chemicals that control blood pressure, prevent blood clots and regulate the body’s response to injury and infection.
Our cave-dwelling ancestors developed a taste for fat as a way to make sure they could pack on extra much-needed kilos to survive in time when food was scarce. Our modern cravings for chocolate brownies or fat-laden creamy sauces and beef dishes are very likely connected to that.
Of course, few of us need extra kilojoules today. And it’s still as important as ever to cut back on saturated fat – fatty meat, butter and cheese – which is a major cause of heart attack, not to mention insulin resistance, the problem at the core of diabetes. However, cutting out all the fat in your diet doesn’t pay off, and that’s because we now know that, far from being deadly, daily doses of certain ‘good fats actually fight disease. Many scientists and nutrition experts now suspect that these unsaturated fats – the ‘good’ fats – inhibit everything from diabetes, depression and dementia to cancer, joint pain and even heart disease.
Replacing some of the kilojoules in your diet that come from saturated fat with kilojoules from unsaturated fat may be even better for you than replacing them with carbohydrate kilojoules. Studies show that swapping saturated fat in your diet for processed, carbohydrate-rich foods, such as white rice and pasta, has only a modest effect on heart disease risk. On the other hand, US researchers studied the diets of 80,000 nurses for 14 years and determined that replacing just 5 percent of kilojoules from saturated fat with an equal amount of good fat may reduce the risk of heart disease by 42 percent.
It’s not just your heart that benefits from these fats, though. Fats can also fight an impressive range of other diseases, as you’ll read later on. But first let’s explain which fats we’re talking about.
DEFINING ‘GOOD’ FATS
As anyone who has ever struggled to lose weight knows, the body is very good at making its own fat, which it stores most prominently on the hips, thighs and around the waist. That’s because your body can, given the right conditions, convert sugar into fat, even if you follow a totally fat-free diet.
However, your body can’t make some types of fatty acids – the building blocks of fat – that are essential to health. That’s why your diet must include the aptly named essential fatty acids, which come primarily from fish and plant oils, and fall into the broader category of polyunsaturated fats. Meanwhile, you can live without eating monounsaturated fats, which form the other major category of unsaturated fat – but mounting research suggests that you may not live as long or as well as people who do consume these other ‘good’ fats regularly.
Scientific trials, such as the Lyon Diet Heart Study, found that eating a so-called Mediterranean diet appears to protect the cardiovascular system more effectively than a typical low-fat one. The cornerstone of a traditional Mediterranean diet is olive oil, one of nature’s richest sources of monounsaturated fat.
In fairness, some of the wonders of the olive may have been overhyped by the cooking oil industry. After all, the traditional Mediterranean diet also includes frequent servings of fruit and vegetables as well as plenty of fish. But it’s hard to ignore the fact that people in this study who ate a Mediterranean type of diet consumed plenty of fat, much of it in the form of monounsaturated fatty acids in olive oil, yet they had four times fewer heart attacks than people asked to eat a standard low-fat diet.
Olive oil isn’t the only excellent source of monounsaturated fat already in your pantry. Its shelfmate, canola oil, is another. Nuts are packed with monounsaturated fats, too, so add nuts, including unprocessed peanut butter, to your shopping list. And the green flesh of an avocado contains nearly as many grams of fat as a fatty hamburger, but the fat is mostly monounsaturated.
Fish oil is the best source of EPA and DHA – two of the beneficial omega-3 fatty acids that have been associated with a large number of health benefits. Eating seafood, especially fatty fish, is your best option for getting omega-3 fatty acids, as the fat that protects all marine creatures from cold water is packed with omega-3s. Choose the fattiest fish possible, such as sardines and salmon, since more oil means more healthy omega-3s, as opposed to the lean cuts of beef and pork you should choose. Canned herring or tuna are other good choices, as are trout, mullet and anchovies. (Avoid taking cod-liver oil, even if you can stand the taste; the recommended doses may contain toxic levels of vitamins A and D.)
If you don’t eat fish, there are other ways to put these fats to work in your body. Fish-oil capsules are one option, though you should talk to your doctor before taking them if you are already taking a blood-thinning medication such as warfarin (Coumadin). Walnuts, walnut oil, canola, linseeds and linseed oil won’t give you exactly the same kind of omega-3s, but they do supply a type of fat called alpha-linolenic acid (ALA), which your body can turn into EPA and DHA and which provides benefits in its own right.
Generally less well-known than the omega-3s are the omega-6s, which are the kind of fat you find in most margarines and vegetable oils. You need some of these to supply essential fatty acids, but most of us consume more than we need.
By the way, all fats and oils contain a blend of saturated, monounsaturated and polyunsaturated fatty acids. But any given fat or oil tends to have a higher concentration of one particular type. For example, 62 percent of the fat in butter is saturated, while 29 percent is monounsaturated and a trace is the polyunsaturated variety. By contrast, just 14 percent of the fat in olive oil is saturated, while 74 per cent is monounsaturated and 8 percent is polyunsaturated. Canola oil contains about 7 percent saturated fat, 60 per cent monounsaturated fat and 30 percent of the total fat is polyunsaturated (one-third of this is ALA).
BETTER FATS, BETTER HEALTH
Are you getting enough ‘good’ dietary fats? 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 daily diet. These versatile fats seem to offer a variety of benefits for the cardiovascular system; likewise, they fight an impressive range of diseases.
MAINTAINING BETTER HARD HEALTH
Every year, many people in Western societies with no prior history of cardiovascular disease die of sudden cardiac death, which occurs when the heart starts beating erratically. Interestingly, one study found that even if every home and public place (such as airports and restaurants) in a community had defibrillators – high-tech machines that are used to shock the heart back into its normal rhythm – only about 1 percent of sudden cardiac deaths would be prevented. Clearly, something else is needed.
By contrast, raising blood levels of omega-3 fatty acids within a population would avert 8 times as many deaths, according to an analysis in the American Journal of Preventive Medicine. To get the necessary level of protection, people would need to take fish-oil supplements, the authors of this say. However, one study of 20,000 men found that simply eating fish once a week slashes the risk of sudden cardiac death in half. Another study found that only one or two servings of fish per month provides similar protection against strokes. The American Heart Foundation recommends eating two to three 150-g servings of fatty fish each week.
It’s not just fish fats that protect 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 servings 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 US Journal of Nutrition. The fat in vegetable oil helps lower cholesterol, too. (The fat in fish has little effect on cholesterol, but it does lower levels of triglycerides, another blood fat linked to heart attacks.)
MORE OIL, LESS 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. These should be eaten instead of, rather than in addition to, sources of saturated fat such as fatty meats, cakes and pastries, and processed snack foods.
Exchanging saturated fat for monounsaturated fat may be even better than exchanging it for carbohydrate. This theory remains somewhat controversial, but research shows that diets high in monounsaturated fat may control blood sugar just as effectively as the typical high-carbohydrate, 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 fats appears to have other benefits you don’t get from a high-carbohydrate 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 diet rich in olive oil and avocados. The study found that switching over to high-carb diet worked, too. However, triglyceride levels dropped 20 percent on the high monounsaturated-fat diet, compared to just 7 percent in those who followed the high-carb diet.
ADDED ANTICANCER BENEFITS
The Lyon Diet Heart Study mentioned earlier 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, appeared to cut their risk of cancer by 61 per cent.
Although many questions remain about the link between diet and cancer, intriguing evidence suggests that healthy fats may protect against some forms of the disease. For example, studies in the 1990s showed that women who consume plenty of olive oil lower their risk of breast cancer by about 25 per cent. More recently, a team of US researchers in Chicago discovered that oleic oil, reduces activity of a gene that causes an aggressive form of breast cancer by 46 per cent. What’s more, oleic acid appeared to increase the effectiveness of trastuzumab (Herceptin), a drug used to treat breast cancer. A second study found that fish oil may offer similar benefits.
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 10am and disappears by 5pm. However, don’t expect to find a bunch of gloomy locals, either. Icelanders have surprisingly low rates of seasonal affective disorder (SAD), which is a mood condition caused by low exposure to sunlight. The secret to their happiness is thought by many to be fish oil.
Consider that the typical Icelander eats four times more seafood than people in Australia and New Zealand. Several other studies have shown that rates of depression tend to be lower in countries where fish is eaten more frequently than it is elsewhere in the world. What’s more, US researchers from the University of Pittsburgh recently found that people who had the highest levels of omega-3 fatty acids in their blood were 53 per cent less likely to report feeling mildly or moderately depressed.
No one is certain why fish oil may help fight the blues, although DHA may affect the formation of chemicals linked to depression. While there’s no guarantee that eating much more salmon, tuna or other fatty fish will start to make you feel happy-go-lucky all of a sudden, some scientists are studying whether having low levels of omega-3s contributes to chronic depression in some people. 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 MEMORY WELL
Think of fish oil as brain food. The body uses its 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 fatty fish may even lower your risk of dementia, the gradual loss of mental ability that sometimes accompanies ageing. For example, US researchers in Chicago found that people who ate fish just once a week reduced their risk of Alzheimer’s disease by 60 per cent. The same research group also found that diets high in saturated fat and trans fat (the kind in processed foods) seem to increase the risk of dementia in some people. What appears to be healthy for preventing cardiovascular disease also appears to be helpful for preventing Alzheimer’s disease and other forms of dementia, according to the researchers on that study. In any case, it makes sense to eat fish for a variety of potential benefits.
Scientists have also linked a deficiency of omega-3s to other cognitive problems, including attention deficit hyperactivity disorder, or 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 US 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 the widely prescribed stimulant drug Ritalin did.
Article written above is mainly derived from FOOD CURES from Reader’s Digest