It is also necessary for producing hormones, vitamin D, and substances that work to digest fatty foods.
However, a person's lifestyle and genetics can cause their body to produce too much cholesterol. When cholesterol builds up in the arteries, it can block blood flow, which can lead to coronary heart disease, heart attack, or stroke.
A healthful diet is one way to help keep cholesterol levels in check. While avoiding foods with high cholesterol content may be beneficial for some, the American Heart Association, National Heart, Lung, and Blood Institute, and Centers for Disease Control and Prevention (CDC) agree that the most effective dietary approach to cutting blood cholesterol is choosing foods that contain unsaturated fats over those that contain saturated or trans fats.
Cholesterol and fats
Cholesterol is classified into two groups, based on the type of protein that transports it through the bloodstream:
- Cholesterol carried by low-density lipoproteins, or LDL cholesterol, is dropped off for use throughout the body. Because this kind of cholesterol is prone to building up, it is often referred to as bad cholesterol.
- Cholesterol carried by high-density lipoproteins, or HDL cholesterol, works together with its protein counterpart like a garbage truck, collecting extra bad cholesterol from the arteries and bringing it back to the liver to be disposed of. For this reason, it's referred to as good cholesterol.
Types of fat
The goal is to eat a diet that promotes low levels of bad cholesterol and high levels of good cholesterol. Fat intake affects this balance because fatty acids bind to liver cells and regulate the production of cholesterol.
Saturated fats are found mostly in dairy and meat products and may increase levels of bad cholesterol.
It is important to pay attention to the types of fat consumed, as each form of fat influences cholesterol levels differently:
- Saturated fats are found mostly in meats and dairy products. They signal the liver to produce more bad cholesterol.
- Unsaturated fats are found mostly in fish, and plants, such as nuts, seeds, beans, and vegetable oils. Certain unsaturated fats can help increase the rate at which the liver reabsorbs and breaks down bad cholesterol.
- Trans fats are solidified vegetable oils, and are usually made through an artificial process called hydrogenation. They are often found in fried, bakery and packaged foods. They not only lead to increased bad cholesterol levels, but also lower levels of good cholesterol. For this reason, they are considered the unhealthiest fats of all.
A study published in The American Journal of Clinical Nutrition caught up with 344,696 participants 4 to 10 years after they changed the kinds of fats they ate. The group of participants who cut their saturated fat intake by 5 percent and replaced it with polyunsaturated fats had significantly fewer incidences of coronary illness or coronary-related death.
Trans fat intake, on the other hand, should not just be reduced but cut out completely. In 2013, the United States Food and Drug Administration (FDA) announced that the major commercial source of trans fats, partially hydrogenated oils, were no longer "generally recognized as safe" because of their strong links to coronary heart disease.
A national ban on trans fats will begin to be implemented in 2018, and several American cities have already banned them from use in restaurants.
While nationwide cardiovascular disease incidences have recently fallen, the results of a recent study in JAMA Cardiology revealed an additional 6.2 percent decrease of heart attack and stroke in the New York counties where trans fats have been banned.
Foods to avoid
Trans fats are found in fried foods and should be avoided whenever possible.
- fatty beef
- poultry with skin
- lard and shortening
- dairy products made from whole or reduced-fat milk
- saturated vegetable oils, such as coconut oil, palm oil, and palm kernel oil
It is also important to avoid trans fats. Foods to stay away from include:
- packaged cookies, cakes, doughnuts, and pastries
- potato chips and crackers
- packaged frosting
- commercially fried foods
- bakery goods that contain shortening
- buttered popcorn
- any products that contain partially hydrogenated or hydrogenated vegetable oils
Cholesterol in foods
Only animal products contain cholesterol itself, as a liver is needed for its production. However, cholesterol content is not as much of a concern as fat content.
Cholesterol that has been swallowed is poorly absorbed into the bloodstream and has little effect on cholesterol levels after several hours. Some of this cholesterol, however, may be absorbed and reach the arteries, so limiting high-cholesterol foods may be beneficial.
Foods that contain cholesterol and may be best avoided include:
- red meat
- organ meats, such as kidney and liver
It is important to note that a completely fat-free diet can also be harmful, because it would deplete the levels of good carbohydrates, impair normal nerve and brain function, and possibly increase inflammation. Choosing healthful fats can help lower bad cholesterol levels, while maintaining, and in some cases increasing, good cholesterol levels.
Nuts and seeds are a cholesterol-friendly fiber option that may be added to a healthful diet.
Fiber is equally important for a healthy heart. Fiber is found in two main forms - soluble and insoluble. Insoluble fiber is important for digestive health. Soluble fiber binds to cholesterol in the bloodstream and helps remove it through stool. Soluble fiber has the added benefit of helping to control blood sugar levels as well.
Some cholesterol-friendly, fiber options to consider include:
- fatty fish, such as salmon, trout, albacore tuna, and sardines
- nuts, seeds, and legumes
- the skins of fruit
- non-tropical natural vegetable oils, such as olive oil, avocado oil, canola oil, and safflower oil
- oats and oat bran, chia and ground flaxseeds, beans, barley, psyllium, oranges, blueberries, and Brussels sprouts
Choose leaner cuts of meat and smaller portions, as well as low-fat or fat-free milk, and yogurts. Non-fat cheese is not recommended as it is highly processed and cannot be considered a whole food.
How things are cooked can also affect the saturated fat content in a meal. Some easy adjustments to cooking routines include:
- using a rack to drain off fat when broiling, roasting, or baking poultry or meats
- using wine in place of fat drippings to baste meat
- broiling or grilling meats instead of pan-frying
- cutting off all visible fat from meat before cooking, and removing the skin from poultry
- skimming off the top layer of congealed fat after a soup has been refrigerated
Combining these cholesterol-cutting techniques with a balanced, plant-heavy diet and an exercise routine, can reduce the risk of heart disease, and will also promote an overall healthier life.