Fats, Oils and Their Impact on Health
Haider Khattak, Food Scientist
Fats are one of the major constituents of the human diet along with carbohydrates and proteins. A major source of energy, they supply about nine calories per gram while one gram of carbohydrates provides four calories, and proteins supply about 4 calories per gram. In calorie deficient situations, fats together with carbohydrates are used by the body instead of protein. Some fatty foods are sources of fat-soluble vitamins, and the ingestion of fat improves the absorption of these vitamins regardless of their source. Fats are vital to a palatable and well-rounded diet and provide linoleic and linolenic, both of which are essential fatty acids.
Essential Fatty Acids have been generally regarded as those that are required by humans but are not synthesized by the body and must be obtained through the diet. The lack of alpha-linolenic acid has been associated with neurological abnormalities and poor growth. A lack of linolenic acid is associated with scaly dermatitis and poor growth. The Institute of Medicine of the National Academies (Dietary Reference Intakes – The National Academies Press 2002) established the first recommended daily intake (RDI) values for linoleic acid at 17 grams for adult men and 12 grams for adult women. The RDI for alpha-linolenic acid was set at 1.6 grams for adult men and 1.1 grams for adult women.
The most important part of our sensory apparatus is our brain. It measures the taste, smell, and mouth-feel of all of the food and drink we consume. When we eat ice cream, it registers the creamy mouth-feel and fatty taste of the ice cream. In recent years, food scientists, chemists, and sensory scientists have created fat substitutes that create a similar response in the brain and give the taste and mouth-feel of fat without the large number of calories associated with it.
People enjoy foods containing fats (lipids) because of the sensory experiences that fat provides – it makes food flavorful, creamy, juicy, smooth, tender, or rich. One can compare the obvious difference easily between whole milk and skimmed milk. We need some fat in our diet but it becomes a problem when we’re consuming too much of it.
In the 1960’s James V. Neel, a geneticist at the University of Michigan, in his “thrifty gene” hypothesis, suggested that some of us inherited genes that make us exceptionally efficient in our intake and use of calories. Our bodies are good at converting food into fat and then hanging on to it. This trait may have helped our ancestors survive when calories were few and far between, Neel speculated.
A typical person has 25 to 35 billion fat cells. The body needs those fat cells to stay healthy. They communicate with the brain, signaling how much energy has been stored and when it is time to eat. They also play an important role in the immune system, helping the body protect itself from cancer and diseases. Fat cells are good for you. But too much of a good thing isn’t good either! An obese person can develop as many as 75 billion fat cells. Once they’re there, it is hard to get rid of them. Becoming obese early in life may fundamentally change a person’s body chemistry, making it difficult to become slim. If one is obese by the age of thirteen, there is a 90 percent chance of being overweight by ones mid-thirties.
Dr. Mehmet Oz is one of New York’s leading heart surgeons who believes that many heart operations could be avoided if people exercised more and ate less fast food. According to him, eating unhealthy foods can damage the brain. Foods that contain too much sugar and the wrong kinds of fats can cause your blood vessels to thicken and narrow. That can limit the amount of blood reaching your brain, reducing its ability to work properly. Atherosclerosis and other heart diseases can be caused by eating certain foods with too much fat in them.
These are both fatty acids with almost the same molecular formulas but different geometric structure. The cis form is the natural one and can be metabolized by the body easily. Trans forms are man-made and difficult to metabolize and accumulate within the arteries. They are suspected of being involved in coronary heart disease. What’s another word for trans fat on the ingredient label? Partially hydrogenated oil. Look out for it in baked goods, peanut butter, cakes, fried chicken, cookies, doughnuts and other fried foods. Trans fats increase the amount of fatty plaque in your blood and may also stiffen your arteries. Researchers at Harvard University believe that trans fats alone are now responsible for the deaths of at least 30,000 Americans every year.
When investigators at the National Academy of Sciences tried to determine how much trans fat a person should eat, they came up with a surprising conclusion: none. In 2006, the US Food and Drug Administration (FDA) made it mandatory for all food and beverage makers to list the trans fat content of packaged foods on the Nutrition Facts label. Further, all fast-food and processed-food companies had to reveal how much trans fat their products contained. As a result, some product labels now state “No Trans Fats”, if there is less than 0.5 grams of trans fat per serving. If there is more than this amount, companies are required to list it on the label in a separate line in the “Total Fat” section of the panel, directly beneath the line for “Saturated Fat.” Zero trans Fat per serving though doesn’t really mean there is no trans fat in a food. It just means each serving could have less than 0.5 grams of it. Have more than a couple of servings and you can be exceeding the trans fat ‘permissible’ level. In 2006, the American Heart Association recommended that you limit the amount of saturated fats to less than 7 percent of your total daily calories, and trans fats to less than 1 percent of total daily calories.
One of the most important recent developments has been the New York City Board of Health’s decision to phase out trans fats in city restaurants. It requires that restaurants limit the amount of trans fats in oils, shortenings and margarine used for frying or in spreads. As of July 2007, restaurants must use less than 0.5 gram per serving. The regulation also requires that, effective July 2008, restaurants limit the amount of trans fats to less than 0.5 gram per serving in all food items not sold in the original manufacturer’s packages. Since then, legislative and regulatory efforts to eliminate trans fats have been proposed in other major cities and states.
Halal Consumer: If trans fat is so damaging, how come it is in so much of our food?
Dr. Chaudry: “One cannot find trans fats on grocery shelves. They are a component of vegetable oils especially partially hydrogenated vegetable oils. Historically, fats used in food were butter, butterfat, tallow and lard. Plant or vegetable oils like olive oil, palm oil, and coconut oil were also used in various cultures. soybean oil and cottonseed oil were not considered favorably as food oils, till technologists discovered a method of processing these oils to make them look and feel like butterfat oil, an all time premium fat. A process called hydrogenation made oils hard like tallow while partial hydrogenation made them softer yet solid like butterfat oil or ghee.”
“Hydrogenation changed the multiple unsaturation points in soybean oil to one or two unsaturation points on each fatty acid. The food industry adopted the process and produced it as an inexpensive source of semi-solid oil with a greater shelf-life, better taste and consumer acceptability. Unknown to the scientific community at that time, the process created an unnatural configuration in the molecular shape of oils to what became known as transfiguration, hence the name trans fats. Over the past two decades harmful effects of trans fats came to light and the regulatory agencies started forcing the industry to remove trans fat from food. At the same time, new and healthier oils have been developed and acceptability of liquid oils amongst consumers has increased to a level that oils are now preferred to fats in ones diet.”
SHORTENING: A blend of fats and/or oils used in baked products, it is solid at room temperature and made with animal fat or vegetable oil.
BUTTER: Butter is a dairy product made by churning fresh or fermented cream or milk.
TALLOW: Solid fats obtained from cattle, sheep or goats. They are used in making shortenings and frying oils.
LARD: It is a solid fat obtained from pigs and used in making shortenings and frying oils.
VEGETABLE OILS: Vegetable fats and oils are derived from plants. Common vegetable oils include coconut oil, safflower oil, sunflower oil, peanut oil, sesame oil, corn oil, cottonseed oil, canola and soybean oil.
MARGARINE: Margarine is a butter-substitute made from vegetable oils in USA and vegetable and animal fats in some other countries.
IFANCA halal-certified vegetable oil companies include: Cargill, Bunge Canada, Cal-Western Packaging