Diet and Cholesterol: What Studies Show

Heart disease and stroke are serious issues for anyone with high cholesterol. But for people with diabetes these two conditions are a special concern, because they account for 65% of early deaths in the diabetes population.1

Drugs called statins are the most commonly prescribed cholesterol-lowering medications.2  Statins lower LDL (bad) cholesterol, lower triglycerides and raise HDL (good) cholesterol.

Dietary Cholesterol: Your body makes most of its own cholesterol, but seafood, dairy products and eggs contain cholesterol, too. However, egg yolks are really the only source of dietary cholesterol that should be of concern because they have a large amount of cholesterol.5HDL: “High-density lipoproteins” are good for you. They bring the cholesterol in the blood back to the liver to get it out of the body. High HDL levels by themselves are good, and food that raises HDL is good.LDL: “Low-density lipoproteins” carry cholesterol away from the liver and throughout the body. A high LDL cholesterol level is harmful because the cholesterol can settle on the walls of arteries, causing hardening and blockages.Total cholesterol: This is the amount of HDL and LDL cholesterol found in the blood.Triglycerides: Triglycerides are another type of fat. They make up the largest portion of fat found in the diet.3 Many doctors believe that high triglyceride levels increase the risk of heart disease. Though triglycerides aren’t actually “cholesterol,” reducing them may help in the same way that reducing cholesterol does.

While statins are good ways to lower cholesterol, you’d be surprised at how much a change in your diet can do. In fact, some changes in diet can lower cholesterol as much as statins do. The easiest diet change you can make is to cut out the ‘bad’ fats. Eat fewer foods that are high in saturated fat, trans fat and dietary cholesterol , or cut them out entirely.

Saturated fats: These fats are found in meat, dairy, seafood and eggs. Some plant products such as palm and coconut oil have high levels of saturated fat, too. Saturated fats raise both the good HDL cholesterol levels and the bad LDL cholesterol levels.

Unsaturated fats: These are found in plant products. They are sometimes called “good fats” because they can raise HDL and lower LDL if they replace other fats in the diet.

Trans fatty acids: These fats come from heating liquid vegetable oils (hydrogenation). Fried foods are high in trans fatty acids. So are many processed foods, snack foods, margarines and baked goods. Trans fats raise the bad LDL cholesterol level and lower the good HDL cholesterol level.4 This makes them even worse than saturated fat in regards to cholesterol.

Eat processed food less often and resist eating too much deep-fried food or food cooked in animal fat. Use egg substitutes instead of regular eggs. Once you’ve cut as much bad fat from your diet as you can, here are some foods you can add because they can actually improve your cholesterol profile.

Fatty Fish
The so-called ‘fatty’ fish include salmon, albacore tuna, sardines, mackerel and herring. The unsaturated fatty acids found in these fish (known as omega-3 fatty acids) are known to lower triglyceride levels in the blood up to 25-30% when eaten once a day.6

Note that fatty fish does NOT lower cholesterol, but by lowering triglycerides, fish can also help reduce risk of heart disease and stroke.

Niacin, also known as Vitamin B3, is found in dairy products, poultry, fish, lean meats, nuts, eggs and to a lesser extent in peas, beans, lentils and enriched breads and cereals. It can also be taken as a supplement. In one recent study, niacin increased HDL ‘good’ cholesterol by 29%, reduced triglyceride levels by 23% and reduced LDL ‘bad’ cholesterol by 8% in people with diabetes.7

For people with diabetes, constant use of niacin will raise blood glucose levels, but at niacin levels between 750-2,000 mg per day, the rise in blood sugar is modest.8

However, you should still talk with your doctor before taking niacin.

Almonds, walnuts, pecans, peanuts and many other nuts are known to lower the ‘bad’ LDL cholesterol. One study that replaced certain daily fats with walnuts found that eating walnuts on a regular basis (1 1/2 to 2 ounces per day) could cut down LDL levels by as much as 9% in men and 10.5% in women.9

In another study, people who added 2 ounces of pecans a day to their diet lowered their LDL cholesterol by 10% and even their triglycerides by 11%. 10

Unsaturated Oils
These cooking oils include canola, corn, soy, peanut and olive oil. They can reduce bad LDL cholesterol without lowering the good HDL cholesterol. One recent study showed that substituting 40% of daily saturated fats with olive oil resulted in a 15% reduction of LDL-cholesterol without significant change in HDL cholesterol.11

Saturated fats like palm oil, coconut oil, lard and shortening can raise LDL cholesterol levels. By using unsaturated oils instead of these other fats, you can fight cholesterol without changing the way you cook.

This versatile bean comes in many forms including the familiar tofu (which takes on the flavors of whatever it is cooked with), soymilk, “meat alternatives” made from soy and other ingredients, and miso (a condiment used to flavor soups and dressings). The cholesterol-lowering powers of soy depend on how much meat and dairy you choose to replace in your daily diet. In dozens of studies, an average of about 1.6 ounces of soy per day was eaten instead of meat. This lowered LDL cholesterol by about 13% and triglycerides by 10.5%, while raising HDL cholesterol by about 2%.12

Soluble Fiber
There are two types of fiber found in food: soluble and insoluble fiber. Soluble fiber can be found in dry beans, oats, psyllium seed (a grain found in some cereals and fiber supplements), citrus fruits and some vegetables. Oatmeal, bean soups and hummus are also good sources. In recent studies, people who ate 0.3-0.4 ounces a day of psyllium had a 7% reduction in LDL cholesterol.13

One cup of whole oats per day lowered LDL by 2%.14

Soluble fiber has the added benefit of stabilizing blood sugar levels in people who have diabetes. A recent study showed that pre-meal blood sugar values were 13mg/dL lower for people eating a diet high in soluble fiber. 15

A word of caution: many foods that are high in soluble fiber are also high in carbs, so talk to your doctor before adding these foods to your diet.

Margarines Enriched With Stanols and Sterols
Plant sterols and stanols are substances that can be found in certain ‘cholesterol lowering’ margarines. The sterol and stanol molecules are similar in shape to cholesterol molecules. They prevent actual cholesterol from being easily absorbed by your digestive tract. In one recent study, people who ate two tablespoons a day of stanol- or sterol-enriched margarine as part of a low-fat, low-cholesterol diet lowered their LDL cholesterol 8% to 13% more than people who ate regular low-fat margarine. 16

Just two to three tablespoons of enriched margarine per day were enough to lower LDL levels. As a result, the FDA has approved cholesterol-lowering health claims for these enriched margarines.

Portfolio Diet (Vegetarian)
So far, we have looked at some individual foods that can lower cholesterol. What if you combine these foods in your diet? Is the cholesterol-lowering effect even greater? One intriguing study suggests that the answer is yes.

In this study, a group of people followed a vegetarian portfolio diet that included margarine fortified with plant sterols, soluble fiber from oats, barley and psyllium, soy as the main protein source, and almonds.17

After 4 weeks on this diet, their LDL cholesterol dropped by 35%, on average. This was similar to the effect of statins, which typically reduce LDL cholesterol by 28-35%.17

So if you are not yet taking statins and you would like to try lowering your cholesterol using diet alone, this portfolio diet approach might work for you. If you are already on statins, you will need to continue taking the pills. But switching to a cholesterol-lowering diet may possibly reduce your dosage of this medication.

In short, the battle against cholesterol can be fought with an arsenal as creative as your grocery cart, even if you already use cholesterol-lowering medication. As one proverb goes, “He that takes medicine and neglects diet, wastes the skills of the physician.”


1. Complications of Diabetes. Accessed May 10, 2004.
2. Statins. National Heart, Lung and Blood Institute Web site. Available at: Accessed July 13, 2004.
3. Medline Plus Medical Encyclopedia: Triglyceride Level. National Library of Medicine Web site. Available at: Accessed May 10, 2004.
4. Fats and Cholesterol. Harvard School of Public Health Web site. Available at: Accessed May 10, 2004.
5. Saudek CD, Rubin RR, Shump CS. The Johns Hopkins Guide to Diabetes for Today and Tomorrow. Baltimore, MD: The Johns Hopkins University Press; 1997.
6. Gylling H, Miettinen TA. A Review of clinical trials in dietary interventions to decrease the incidence of coronary artery disease. [Current Controlled Trials in Cardiovascular Medicine Web site] Available at: Accessed May 10, 2004
7. Elam MB, Hunninghake DB, Davis KB, Garg R, et al, for the ADMIT Investigators. Effect of niacin on lipid and lipoprotein levels and glycemic control in patients with diabetes and peripheral arterial disease (The ADMIT study: a randomized trial). JAMA. September 13, 2000; 284;No. 10:1263-1270.
8. American Diabetes Association. Standards of Medical Care in Diabetes. Diabetes Care. 2004; 27(Suppl 1): S15-S35.
9. Iwamoto M, Imaizumi K, Sato M, et al. Serum lipid profiles in Japanese women and men during consumption of walnuts. European Journal of Clinical Nutrition. 2002; 56:629-37.
10. Rajaram S, Burke K, Connell B, et al. A monounsaturated fatty acid-rich pecan-enriched diet favorably alters the serum lipid profile of healthy men and women. Journal of Nutrition. 2001;131:2275-2279.
11. Roche HM, Zampelas A, Knapper JME, et al. Effect of long-term olive oil dietary intervention on postprandial triaglycerol and factor VII metabolism. American Journal of Clinical Nutrition. 1998; 68:552-560.
12. Anderson JW, Johnstone BM, Cook-Newell ME. Meta-Analysis of the Effects of Soy Protein Intake on Serum Lipids. The New England Journal of Medicine. 1995; 333:276-282.
13. Anderson JW, Allgood LD, Lawrence A, Altringer LA, Jerdack GR, Hengehold DA, Morel JG. Cholesterol-lowering effects of psyllium intake adjunctive in men and women with hypercholesterolemia: meta-analysis of 8 controlled trials. The American Journal of Clinical Nutrition. 2000;71:472-479.
14. Brown L, Rosner B, Willet WW, Sacks FM. Cholesterol-lowering effects of dietary fiber: a meta-analysis. American Journal of Clinical Nutrition. 1999:69:30-42.
15. Chandalia M, Garg A, Lutjohahn D, et al. Beneficial effects of high dietary fiber intake in patients with type 2 diabetes mellitus. New England Journal of Medicine [serial online]. 2000; 342:1392-1398. Available at: Accessed May 10, 2004.
16. Hallikainen MA, Uusitupa MIJ. Effects of two low-fat stanol ester-containing margarines on serum cholesterol concentrations as part of a low-fat diet in hypercholesterolemic subjects. American Journal of Clinical Nutrition. 1999; 69:403-410.
17. Jenkins DJA, Kendall CWC, Marchie A. The effect of combining plant sterols, soy protein, viscous fibers, and almonds in treating hypercholesterolemia. Metabolism. 2003; 52;No 11:1478-1483.


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