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James L. Holly, M.D. |
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| James L. Holly,M.D. |
| January 09, 2003 |
| Your Life Your Health - The Examiner |
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If low-fat is good, then no-fat must be better, right? Wrong. Fat is an important part of every diet, and it is particularly important for infants and young children. Severely restricted diets in fat can impair neurological and mental development in children. Now, that doesn't mean that every child needs a Big Mac every day, but it does mean that a healthy part of every diet is the right amount and the right "kind" of fat.
Fat
The December 4, 1995 issue of The Food Institute Report stated, "When reading labels, 87% of Americans are concerned with the fat content of food while half pay close attention to the cholesterol." This is a result of numerous studies that have linked high-fat diets to heart disease, cancer, obesity and many other diseases. With the great amount of attention on how "bad" fat is, it mustn't be forgotten that fat is an essential part of a healthy diet. Many people have gone to excess with the low-fat and fat-free craze. Likewise, the food industry has perpetuated this by manufacturing food products that are low-fat, light, or fat-free.
You might be surprised to find out the actual amount of fat that is recommended to eat each day. We mentioned last week that our daily caloric intake should consist of less than 30% of total calories from fat. When using John's 2000 kcal/day diet, that would mean he'd need to eat less than 67 fat grams each day. Some people may claim that's too much fat, but to maintain a healthy weight and lifestyle, that is the upper scale of the limit. Of course receiving 20% of your calories from fat is better and even then the equivalent in fat grams equals 44 g. To follow a general guideline, you should eat between 20 to 40 g of fat, minimum. Even those extremists who claim to eat no fat at all, are eating fat. Everything has traces of fat, even broccoli has traces of fat.
Fat is an essential aspect of a healthy diet. It provides a supply of essential fatty acids that the body needs for proper functioning. They are the basic building blocks for prostaglandins, a type of hormone, which help control blood pressure, blood clotting, inflammation, and other bodily functions. Linoleic acid is the most important of the essential fatty acids and helps with proper growth and development of infants. Another function of fat is that it serves as storage for the body's excess calories, in adipose tissue. The fat storage is utilized for energy 20-30 minutes after aerobic exercise begins and after the immediate stored carbohydrates are used (after the first 20 minutes).
Fat not only is utilized for energy but also helps with maintaining healthy skin and hair, transports fat-soluble vitamins (A, D, K, & E) throughout the blood stream, regulates blood cholesterol levels, and helps you feel full when eating (takes longer to digest in the stomach and slows emptying of the stomach).
The types of fat you consume are also very important to a healthy diet. Fats are also known as lipids and come in liquid and solid forms. Triglycerides compose most of the fats in foods. They are made up of three fatty acids and a glycerol molecule and vary in saturation of hydrogen atoms. This saturation is what determines the different properties of fats. There are two kinds: saturated fatty acids and unsaturated fatty acids.
- Saturated fatty acids are full of hydrogen atoms and are solid at room temperature. These fats come primarily from animal sources such as butter, dairy products, and meats, but coconut and palm oils are also highly saturated. A diet high in saturated fats can lead to an increase in blood cholesterol levels which may lead to heart disease.
- Unsaturated fatty acids are under two categories depending on the amount of hydrogens attached.
- Monounsaturated are found in olive, canola, peanut, and avocado oils.
- Polyunsaturated fats are found in corn, safflower, and sesame oils. Your dietary fat should come primarily from these unsaturated sources.
An easy way to remember the difference is that saturated fats are solid at room temperature and unsaturated fats are liquid at room temperature. Of course, this is not always true, there are always exceptions to the rules. Be sure to read your Nutrition Facts Label on processed foods because there are many hidden saturated fats in processed foods (i.e. movie popcorn) that you would not think of as extremely fattening.
Cholesterol
Cholesterol is in all of our body's tissues, but the serum cholesterol, the cholesterol in the blood, is what we should be concerned with. Blood cholesterol can accumulate along the blood vessel walls causing atherosclerosis (hard plaque build up) which could lead to a possible heart attack or stroke. High cholesterol (>200 mg/dl ) along with the risk factors of high blood pressure, family history of heart disease, obesity, diabetes, and smoking are especially dangerous. Cholesterol is found in all animal products, including our own bodies.
Our liver manufactures the cholesterol necessary for our body, but it is the excessive dietary intake of high-fat animal products which makes the cholesterol levels such an issue. There is actually little research supporting high dietary cholesterol intake and high blood cholesterol levels. There is more of a genetic link which gives a person a sensitivity to dietary cholesterol. It is recommended to keep your cholesterol intake to no more than 300 milligrams per day. This is easily attainable by sticking to a diet that is low in fat and high in fruit and vegetables. Be aware of products that say "no cholesterol." Any product that does not have animal by-products is cholesterol free. That does not mean it is fat free. The product still may contain lots of fat from vegetable oils. Many manufacturers like to point out that there is no cholesterol, but fail to recognize the fat content. Remember: Always read your Nutrition Facts Label.
Cholesterol is made up of different types of lipoproteins. LDL (low density lipoprotein), VLDL (very low density lipoprotein), and HDL (high density lipoprotein) are the three categories. LDL's, also known as "bad" cholesterol, are made when there is a high consumption of saturated fats. According to some recent studies, both polyunsaturated fats and monounsaturated fats actually help reduce the amount of LDL cholesterol, and therefore help reduce the total amount of artery clogging cholesterol in the blood.
HDL cholesterol, or the "good" cholesterol, is so great because it has the ability to pick up "bad" cholesterol from cells in the body and return it to the liver for excretion in the urine. There is no proven way to increase your HDL cholesterol, except exercise has proven to show some benefit.
What is your cholesterol level?
If you don't know, please check with your doctor about finding out. Many health and wellness centers offer very inexpensive cholesterol screenings. Again, remember to ask what your HDL level is as well as your total serum cholesterol level. The desirable range for cholesterol levels are between 140-220 mg/dl. For children: 70-175 mg/dl. An HDL level that is greater than 35 mg/dl is desirable as well.
What should your cholesterol be?
The original studies done on the association between cholesterol levels and heart disease were in the Framingham study. In that study, the relationship between the total cholesterol and the HDL were considered to be the most important factors in predicting future heart problems. Now, we know that while that is important, the most important consideration is your LDL. And, the best practices are now aggressively treating LDL to reduce it below 70.
Exercise and diet are important in treating cholesterol, but for most people with an LDL above 130 and total cholesterol about 180, it will take medication to get the desired result.
There is strong evidence that if you can get your LDL below 70 and your Cholesterol/HDL ration below 3.0 that it is highly improbable that you will ever develop atherosclerotic heart disease.
Next week, we'll continue this series with another discussion of vitamins and minerals.
Remember, it is your life and it is your health.
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