Homocysteine, lipoprotein (little a), insulin and free radicals may all play a role in cardiovascular disease, but none are likely to prove as important as high LDL, the bad cholesterol. Indeed, a recent prospective study failed to confirm homocysteine as a risk factor for coronary heart disease, althought it did find an association with low levels of Vitamin B-6. Smoking and hypertension are the other two major risk factors for heart disease but their combined effects in someone with a total cholesterol below 185 appear no greater than simply having a total cholesterol above 245.
A high total cholesterol is generally due to a high level of LDL and the American Heart Association and the National Cholesterol Education Program now recommend that for high risk individuals, LDL should be less than 100.
There are many nutritional factors that push LDL up and down. This month we will focus on changes in the diet that can push LDL down to safer levels. Next month we will discuss the nutritional factors that cause LDL to rise.
Weight loss is generally associated with a modest reduction in LDL. Some of this reduction may be due to a reduction in dietary factors that raise LDL. During active weight loss, HDL, the good cholesterol, often drops but usually recovers to higher than pre-diet levels if a lower weight is maintained. Since weight loss reduces other coronary heart disease risk factors like high insulin, diabetes, hypertension and high triglycerides, its benefits generally far exceed its relatively modest cholesterol lowering effect.
An often overlooked strategy for lowering LDL is increasing meal frequency. Most studies show a significant reduction in LDL with no change in HDL. Smaller but more frequent meals appear to lower LDL by reducing cholesterol synthesis in the liver. Going from 1-2 very large meals to 6 or 8 small meals daily can often lower LDL by 10% or more with no change in diet composition or calorie intake.
Increasing dietary fiber, particulary soluble fibers like pectins and gums found in legumes, fruits and root vegetables, as well as oats and barley are perhaps the safest and most effective of the dietary factors that lower LDL. Psyllium husks (the richest natural source of soluble fiber) lowers LDL about 1% for each gram consumed daily. Soluble fibers lower LDL with little or no effect on HDL so the ratio of HDL/LDL improves with increasing fiber.
Two other little appreciated dietary factors that can lower LDL are plant sterols and proteins. Substituting vegetable proteins for animal proteins lowers LDL particulary in people with high cholesterol. This protein effect has been shown to occur with purified proteins devoid of all fatty materials and cholesterol. Plant sterols (i.e. beta sitosterol) lower serum LDL about as much as dietary cholesterol raises it. Plant sterols appear to work primarily by reducing absorption of cholesterol from the gut.
The best studied dietary factors influencing LDL are fatty acids. Both monunsaturated fats and polyunsaturated fats are claimed to lower LDL when they replace saturated fat. Most research actually shows that monounsaturated fats are neutral (neither raising nor lowering LDL) while omega 6 polyunsaturated fats, found in large amounts in corn and safflower oils, actively lower LDL about half as much as saturated fats raise LDL.
By contrast, omega 3 polyunsaturated fats (found in fish and flax) are more likely to increase LDL than to lower it although there is considerable individual variability in this response. Nevertheless, perhaps because fish oils decrease triglycerides and reduce the tendency of blood to clot, consuming about 7 ounces of fish a week was significantly associated with decreased coronary heart disease and total mortality. It is important to note that more fish was not more protective in this study - more fish increases LDL.
Dr. Jay Kenney, PhD, RD, FACN.
5 Top Strategies to Lower LDL
1. Consume plant foods that are high in fiber, especially soluble fiber. Soluble fiber is found in legumes, fruits and root vegetables, as well as oats, barley and flax. See the chart below for a list of suggestions. For every one gram of soluble fiber you consume, you help lower your LDL by 1%. Experts recommend that you try to consume 15 grams of soluble fiber per day.
2. Eat 6 to 8 small meals daily instead of one or two large ones.
3. Eat a plant based diet with a minimum amount of lean animal protein. Serve most of your meals based on beans, vegetables, fruits and whole grains.
4. Exercise at least 30 minutes per day, ideally 4-5 times per week.
5. Lose weight. Weight loss of ten pounds is enough to lower your LDL. This is because people who lose weight tend to eat more things that lower cholesterol and less things that raise their cholesterol.
Judy’s passion for cooking began with helping her grandmother make raisin oatmeal for breakfast. From there she earned her first food service job at 15, was accepted to the world famous Culinary Institute of America at 18 (where she graduated second in her class), and went on to the Fachschule Richemont in Switzerland where she focused on pastry arts and baking. But after learning that the quality of a croissant directly varies with how much butter it has, Judy sought to challenge herself by coming up with recipes that were as healthy as they were tasty.
Judy received The Culinary Institute of America’s Pro Chef II certification, the American Culinary Federation Bronze Medal, Gold Medal, and ACF Chef of the Year. Her enthusiasm for eating nutritiously and deliciously leads her to constantly innovate and use the latest in nutritional science to guide her creativity, from putting new twists on fajitas to adapting Italian brownies to include ingredients like toasted nuts and cooked honey. Judy’s publishing company, Food and Health Communications, is dedicated to her vision that everyone can make food that tastes as good as it is for you.