Can you improve cholesterol through diet changes?

While dietary cholesterol isn't as important as once thought, research suggests eating the right fats and carbs can help lower LDL cholesterol levels.

WRITTEN BY

Stephanie Eckelkamp

REVIEWED BY

Dr. Rich Joseph

UPDATED: 12 Dec 2024

PUBLISHED: 12 Dec 2024

🕗 9 MIN READ

If you're thinking about cholesterol, it's probably because a doctor told you after a recent physical or blood test that you needed to lower yours. Cholesterol is the most well-known biomarker because of its decades-long association with cardiovascular disease, the leading cause of death in the U.S. But it's also one of the most misunderstood.

Cholesterol is a lipid, or fat-like substance, primarily produced by the liver. It's carried through the bloodstream as a component of lipoproteins (lipid-protein complexes), and it can be taken up by cells and used for processes like the production of hormones and bile.

Cholesterol isn't inherently bad, but it's well-established that high LDL (low-density lipoprotein) cholesterol levels can contribute to plaque buildup on artery walls. Continued plaque buildup over time can cause arteries to narrow and stiffen, impairing blood flow and driving cardiovascular disease (including heart attacks) and cerebrovascular disease (stroke).

High HDL (high-density lipoprotein) cholesterol levels have a somewhat protective effect on cardiovascular health. This is why people refer to LDL as "bad" cholesterol and HDL as "good" cholesterol, though that's an oversimplification.

If you're trying to lower your cholesterol levels, there are a few proven ways to do so, and your best bet is to work with your doctor to find the best combination. Medications like statins are the most popular and are effective, but may not be feasible for all who qualify, given certain established side effects. Exercise is another proven strategy. Finally, there's diet.

Research shows that diet changes can improve your cholesterol profile, which can reduce cardiovascular risk. However, there is some debate among experts about which foods and nutrients are the most problematic or helpful, and the impact of dietary changes alone may not be enough to reach optimal levels for some people. Finally, research also suggests that there are genetic differences in how people absorb cholesterol in their gut, which can affect how effective diet changes can be in improving cholesterol levels.

Below, we'll explain how cholesterol works in the body and what dietary changes may impact your levels.

Why cholesterol matters

In some people, LDL becomes elevated due to dietary habits or genetic disorders that interfere with LDL clearance from the blood, cholesterol synthesis, and other processes.

• Your eating habits influence 20 to 30 percent of the cholesterol in your bloodstream. For example, certain nutrients can decrease or increase the number of LDL receptors on cells, causing LDL levels to rise or fall, while others may increase cholesterol production by the liver. (More details on specific nutrients later.)
• Familial hypercholesterolemia (FH) interferes with the body's ability to process LDL, often due to a mutation in the gene that codes for LDL receptors. In people with this disorder, LDL cholesterol levels may be two to four times higher (or more) than what's considered normal (about 190 to 400 mg/dL or more). FH affects about one in every 250 people in the U.S.; statin medication is typically needed to get LDL into a safe range.

The most common way to assess cardiovascular disease risk and learn your cholesterol numbers is with a lipid panel blood test, which measures total cholesterol, LDL, HDL, and triglycerides. Total cholesterol is considered "high" if it's 190 mg/dL or higher, but there isn't much value in focusing on this number in isolation. Instead, the emphasis is usually placed on keeping atherogenic LDL relatively low and protective HDL relatively high. Current U.S. guidelines suggest levels of LDL 100 mg/dL or lower (130 mg/dL and greater is considered "high"; some Levels advisors recommend <70 mg/dL); evidence suggests that generally, the lower the LDL levels, the lower the cardiovascular risk. For HDL, guidelines suggest 60 mg/dL or higher.

However, there are downsides to using LDL cholesterol as a primary marker to predict CVD risk. It only tells you the concentration, or mass, of cholesterol in the blood but says nothing about two arguably more important factors: 1) the total number of LDL particles and other atherogenic lipoproteins in the blood, and 2) the size of LDL particles. Both of these have been shown to portray someone's CVD risk more accurately.

For this reason, many doctors suggest tests such as ApoB, which is a measurement of all atherogenic particles in the blood (LDL, VLDL, IDL, and Lp(a)), and NMR lipoprotein fractionation, which measures the total number of LDL particles and relative amounts of small versus large LDL particles. Additionally, getting a separate blood test for Lp(a) may be warranted, particularly if you have a family history of heart disease. This lipoprotein is elevated in about 20--30% of the population and significantly increases risk of CVD, even in the absence of high cholesterol. Lp(a) levels are mainly due to genetics and don't respond to lifestyle interventions. So if your Lp(a) levels are high (above 30-50 mg/dL), it becomes even more important to optimize all modifiable risk factors for cardiovascular health, such as cholesterol, blood pressure, triglycerides, and body weight, to curb overall CVD risk.

What to know about cholesterol and your diet

What you eat can influence levels of LDL and HDL cholesterol, LDL particle size, and other important factors, such as whether or not LDL cholesterol is likely to become oxidized and, therefore, more dangerous. However, there's some debate about the best dietary approach to optimizing cholesterol.

It's not about dietary cholesterol (for most people)

For nearly half a century, medical professionals advised people to limit their dietary cholesterol intake from sources like eggs, processed meats, and full-fat dairy to less than 300 mg daily to help lower blood cholesterol and curb CVD risk. Today, most research suggests cholesterol from food has little to no impact on blood cholesterol for most people. That's because as you consume cholesterol, the body activates compensatory mechanisms like increasing cholesterol excretion and decreasing cholesterol synthesis.

That said, some people are considered cholesterol "hyper-responders" and have a greater than normal response to dietary cholesterol (estimates range from about 15-25% of the population). However, some studies suggest that LDL and HDL cholesterol rise equally in these people, and lipoprotein particle size may also increase in response to dietary cholesterol intake, which could mitigate some of the risk.

Another important variation among people is intestinal cholesterol absorption---basically, how much dietary cholesterol gets absorbed into the bloodstream through the small intestine. Research shows the absorption rate can range from 29--80% between individuals and is influenced largely by genetics, as well as diet, age, microbiome, and other factors. Those who absorb more cholesterol have a higher cardiovascular risk, although there are medications that can influence absorption.

Given the weak link between dietary and blood cholesterol, the recommendation to cap cholesterol at 300 mg per day was removed from the Dietary Guidelines for Americans in 2015---but the guidelines still suggest keeping cholesterol intake relatively low. The likely rationale for this is that dietary cholesterol is often found in foods that also contain high levels of saturated fat (think: processed meats), and a large body of evidence suggests that excess saturated fat increases LDL cholesterol and potentially CVD risk.

The takeaway: Eating foods that contain cholesterol is unlikely to pose a health risk, provided the amount eaten doesn't lead to excessive saturated fat intake.

How do dietary fats affect cholesterol levels?

Different fats have different effects on blood lipids like cholesterol. For an optimal cholesterol profile, the American Heart Association (AHA) and the Dietary Guidelines for Americans suggest:

• Avoiding trans fats
• Reducing saturated fat intake to 10 percent of your total daily calories (less than 22 grams if you eat 2,000 calories) or 5 to 6 percent (about 13 grams) if you already have CVD risk factors, such as high cholesterol
• Prioritizing polyunsaturated fats (PUFAs) and monounsaturated fats (MUFAs)

One thing everyone can agree on: Trans fats are bad, as they lower HDL, raise LDL, reduce LDL particle size, and contribute to oxidative stress. Fortunately, the Food and Drug Administration (FDA) now prohibits food manufacturers from adding partially hydrogenated oils (the primary source of artificial trans fats) to their products. Additionally, the small amount of trans fats naturally occurring in meat and dairy doesn't appear to impact cholesterol levels.

The impact of saturated fat on cholesterol and CVD risk is more nuanced and debated. Research suggests that eating high amounts of saturated fat---found in foods like meat, eggs, dairy products, and tropical oils like coconut and palm---can increase LDL cholesterol by decreasing the number of LDL receptors on liver cells (which reduces clearance of LDL from the blood) and increasing cholesterol biosynthesis.

However, other research suggests that saturated fat predominantly promotes the production of the more benign large LDL particles, which may pose less risk. Additionally, several studies have found no association between CVD and certain minimally processed foods containing saturated fats, such as unprocessed meats, whole-fat dairy, and dark chocolate. This might suggest that the disease-promoting potential of saturated fat depends on what other ingredients are present in a food and what someone's overall diet looks like.

Genetics and lifestyle also play a role in determining how significantly saturated fat impacts cholesterol levels and CVD risk. Getting regular blood lipid testing can help you understand your individual response to different levels of saturated fat intake. While you don't need to eliminate saturated fats altogether, it's essential to be mindful of the context of your intake.

On the other hand, some fats are known to promote healthy cholesterol levels. Diets containing a higher percentage of MUFAs and PUFAs than saturated fats tend to be associated with lower LDL cholesterol and CVD risk.

How does carbohydrate intake affect cholesterol levels? 

Regularly eating more calories than you burn, particularly from low-quality carbohydrates, increases the liver's production of triglycerides, another lipid that can contribute to CVD. Research suggests excessive carbs may also ramp up cholesterol, but less directly.

Eating excessive carbohydrates---especially highly processed or refined carbs and sugars that your body rapidly breaks down and absorbs---contributes to blood sugar spikes and subsequent surges in insulin that can lead to insulin resistance. And insulin resistance-induced dyslipidemia is characterized by an increase in small, dense LDL particles---the more dangerous variety.

Additionally, high intake of carbs---particularly concentrated sources of fructose from things like juice and sugary beverages---can contribute to accumulated stored fat (as triglycerides) in the liver. This may progress to non-alcoholic fatty liver disease (NAFLD). NAFLD is associated with insulin resistance, and it interferes with a variety of other mechanisms involved in cholesterol clearance and metabolism, which can drive up LDL. For example, it can damage LDL receptors on liver cells and downregulate LDL receptor gene expression, thereby preventing appropriate uptake of LDL cholesterol from the bloodstream. It can also interfere with the ability of the enzyme HMG-CoA reductase to downregulate cholesterol synthesis.

At the same time, the effects of low-carb and keto diets on cholesterol are unclear. Some studies show LDL cholesterol remains unchanged on these diets, some show it decreases, and some show it increases significantly in a subset of people considered "lean mass hyper-responders." And other studies have found going low-carb may help transform LDL cholesterol particles into the larger, more benign form. Given these varied results, it may be smart to get baseline blood lipid testing if or when you transition to a low-carb diet and periodic follow-up testing to track your response.

Still, carbs aren't the enemy. Whole and minimally processed carb-containing foods (such as fruits, vegetables, legumes, and whole grains) are packed with compounds like soluble fiber, phytosterols, and antioxidants, all of which can help lower cholesterol or prevent it from becoming oxidized and, therefore, more harmful.

What foods can help lower cholesterol?

Now that you know some broad nutritional factors that influence cholesterol levels in the body, let's explore some specific foods and nutrients to consider prioritizing.

1. Foods high in soluble fiber

Generally, fiber helps curb appetite, stabilize blood sugar, and support cardiovascular health. And soluble fiber specifically helps lower LDL cholesterol via the following mechanisms:

• Soluble fiber forms a viscous gel in the intestines, allowing it to trap and eliminate bile acids (composed mainly of cholesterol) from the body via feces. Because 95 percent of bile acids are usually reabsorbed and recycled, the increased elimination means that the liver must synthesize new bile from cholesterol. To accommodate this, LDL receptors are upregulated in liver cells. This increases LDL cholesterol uptake by the liver and lowers circulating LDL cholesterol levels in the blood.
• Soluble fibers feed beneficial bacteria in the colon, which produces short-chain fatty acids (SCFAs). Research suggests that, among their many positive effects, SCFAs like butyrate may help decrease cholesterol synthesis by interfering with the activity of the enzyme HMG-CoA reductase.

Eating five to 10 grams of soluble fiber daily has been shown to lower LDL cholesterol by five to 11 points. The following are good sources of fiber:

• Legumes (beans, lentils, chickpeas, peas)
• Avocados
• Broccoli
• Brussels sprouts
• Sweet potatoes
• Carrots
• Pears
• Figs
• Oranges
• Raspberries
• Chia and flax seeds
• Oats
• Quinoa

A good strategy: Aim for 35 to 50 grams of fiber daily, which should cover your bases. If you're struggling, you can add a one-teaspoon serving of supplemental psyllium fiber (which has 3 grams of soluble fiber) mixed with water before meals. Several studies.) have shown that six to 15 grams per day of supplemental psyllium fiber may lower LDL cholesterol by 6 to 24 percent.

2. Colorful, antioxidant-rich plant foods

A growing body of research suggests that arterial plaque formation and atherosclerosis are more likely to occur when circulating LDL cholesterol is exposed to free radicals (from processed foods, environmental toxins, and more) and undergoes oxidation. Fortunately, consuming foods rich in antioxidants can help neutralize free radicals and reduce their harmful effects on LDL.

Studies have shown that foods containing the following classes of antioxidant compounds can help protect LDL cholesterol from oxidation:

• Carotenoids (lycopene, lutein, zeaxanthin, beta-carotene): found in tomatoes, carrots, spinach, arugula, broccoli, avocado, sweet potatoes, squash, cantaloupe, and watermelon
• Polyphenols (flavonoids and phenolic acids): found in grapes, berries, oranges, grapefruit, tea, dark chocolate, olives, extra-virgin olive oil, red cabbage, spinach, nuts (particularly walnuts), seeds, turmeric, ginger, chili peppers, onions, and minimally processed soy foods (e.g., edamame, tofu, tempeh)
• Vitamin C: found in citrus fruits, bell peppers, broccoli, kiwi, strawberries, Brussels sprouts, cantaloupe, cabbage, cauliflower, and more

Emerging research also suggests that some of these same antioxidant-rich foods may enhance HDL cholesterol's%2C%20and%20cholesteryl%20ester%20transfer) anti-inflammatory and antioxidant properties and its ability to shuttle cholesterol back to the liver for disposal.

3. Fatty fish rich in omega 3s

Several studies have shown that consuming fatty fish such as salmon, mackerel, and sardines---but not leaner varieties of fish---may help improve your overall cholesterol and blood lipid profile by increasing HDL cholesterol and reducing triglycerides. The beneficial impact of eating more fatty fish may be even greater when fish replace low-quality protein sources high in saturated fats, such as bacon, sausage, hot dogs, ham, salami, and other highly processed meats. No wonder the AHA recommends two 3-ounce servings of fish---ideally fatty fish---per week, as omega 3s have been shown to reduce the risk of heart attack and stroke.

However, fish oil supplements may be less beneficial. In a 2017 study, researchers found that consumption of fresh fatty fish (nearly 9 ounces for lunch and dinner two days per week for a total of eight weeks) was better at lowering total cholesterol, LDL cholesterol, and triglycerides, and at increasing HDL cholesterol compared to taking 2 grams of fish oil per day. And in a 2023 study, fish oil supplements lowered non-HDL cholesterol and triglycerides, but only at doses greater than 2 grams per day. The increased benefits of fatty fish may be due to additional nutrients in fish, including selenium, vitamin D, and various antioxidants.

4. Nuts and seeds

Don't eat fish? Snacking on certain nuts and seeds can provide a dose of the plant-based omega-3 alpha-linolenic acid (ALA), along with additional nutrients that appear to affect optimizing cholesterol levels in the body synergistically.

While nuts in general are a good source of%20concentrations%20(12).) MUFAs, PUFAs, fiber, vitamins, minerals, polyphenol antioxidants, and phytosterols, walnuts are the only nut with meaningful quantities of ALA, which has anti-inflammatory and anti-atherogenic properties. Walnuts also have the highest levels of polyphenols of any nut, which can help counter the oxidation of LDL cholesterol. In a 2018 review, walnut-enriched diets were associated with lower total cholesterol, LDL cholesterol, triglycerides, and ApoB compared to control diets that didn't contain walnuts. While the amount of walnuts consumed varied by study, benefits were highest for those who ate at least 28 g (one ounce) per day. However, those who ate less than this still experienced benefits to total cholesterol and LDL cholesterol.

Seeds have a nutrient profile similar to nuts, and flaxseeds are a particularly good source of ALA, soluble fiber, and a group of polyphenols called lignans. A 2020 meta-analysis found that consuming 10 to 60 grams of flaxseeds daily (about 1.5 to 9 tablespoons) may lower total cholesterol, LDL cholesterol, and triglycerides. Ground flaxseed is the preferred form, as its nutrients are the most bioavailable, and you can easily add it to yogurt, smoothies, oatmeal, and baked goods, or use it as "bread crumbs" in salmon patties and chicken tenders.

5. MUFA-rich cooking oils

If you prepare a lot of food at home, one of your biggest sources of dietary fat could be the oil you use to make salad dressings, stir-fry veggies, pan-sear proteins, or drizzle on top of finished dishes. So consider upgrading to cholesterol-friendly extra-virgin olive oil (EVOO) and avocado oil. Both are predominantly composed of monounsaturated fats, or MUFAs.

Compared to PUFA-rich vegetable and seed oils, EVOO is more stable and generally less prone to oxidation when heated. And given what we know about the increased dangers of oxidized LDL cholesterol, this is important. MUFAs have been shown to increase HDL cholesterol levels and reduce levels of the inflammatory marker C-reactive protein when added to therapeutic diets already low in saturated fat. They may also lower LDL cholesterol when used in place of cooking fats and oils high in saturated fat, such as butter, lard, palm oil, and coconut oil.

EVOO packs an extra punch, given its high levels of polyphenols, including hydroxytyrosol and oleuropein. These have been shown to help prevent the oxidation of LDL and HDL cholesterol particles in a dose-dependent manner (meaning, higher intake tends to increase the benefit).

6. Avocados

MUFA-rich foods are great, too, especially avocados. The fat in avocado oil is about 71 percent MUFAs, but these fatty fruits also contain an array of other beneficial compounds that likely contribute to their blood lipid benefits, such as soluble fiber, carotenoid antioxidants (lutein and zeaxanthin), phytosterols, and a variety of vitamins and minerals. Add avocado to smoothies, salads, desserts, omelets, and sandwiches and wraps.

7. Whey protein

If you're trying to choose between protein powders, some research suggests whey protein could be your best bet for lowering cholesterol. A 2020 meta-analysis of 22 studies on participants with metabolic syndrome found that consuming whey protein improved several markers of metabolic health, including reductions in total cholesterol, LDL cholesterol, triglycerides, HbA1c, and insulin.

The study's authors suggest several potential mechanisms:

• The calcium in whey may decrease dietary fat absorption
• Beta-lactoglobulin and sphingolipid compounds may decrease dietary cholesterol absorption
• Branched-chain amino acids (BCAAS) have been associated with down-regulation of genes that influence cholesterol absorption

Plus, getting enough protein is essential for supporting overall blood sugar balance and lowering the risk of insulin resistance, which is known to negatively impact blood lipids and increase small, dense LDL particles.

What to reduce or avoid to lower cholesterol

While we touched on some potentially problematic foods and nutrients above, let's recap the main offenders that you may want to reduce to optimize cholesterol:

• Highly processed saturated fats: Consider upgrading your fat intake by replacing the most highly processed forms of saturated fat in your diet (e.g., processed meats, desserts, fast food) with unsaturated fats from foods like olive oil, olives, avocados, nuts, seeds, and fatty fish.
• Trans fats from fried foods: While partially hydrogenated oils have been banned from the U.S. food supply, trans fats may still be present in fried foods as they are a byproduct of the heating of seed oils used in deep fryers. Try to limit or avoid french fries, fried chicken, and other fried foods.
• Sugars and refined carbohydrates: Due to their potential negative impact on blood sugar, insulin, and the accumulation of liver fat---which may increase levels of small, dense LDL cholesterol---keeping these foods to a minimum will help promote a healthier cholesterol profile and support overall metabolic health.

Other ways to lower high cholesterol

Although changing your diet can have a positive impact, the best approach to lowering cholesterol is holistic, and your doctor may suggest supplementing lifestyle changes with medication. Here are some effective habits:

• Exercise: Various forms of exercise, including brisk walking, jogging, cycling, and resistance training, have been shown to lower LDL cholesterol. But, a combination of aerobic and resistance exercise may be best for raising HDL and lowering LDL.
• Drink in moderation, if at all: Heavy drinking increases triglyceride levels and can raise cholesterol levels. Similar to excess sugar intake, consuming too much alcohol can contribute to the buildup of fat in the liver (i.e. fatty liver), which interferes with normal cholesterol clearance and metabolism.
• Don't smoke: Both smoking and vaping can lower levels of beneficial HDL cholesterol. Smoking also contributes to the production of free radicals and a state of oxidative stress in the body and is associated with increased levels of oxidized LDL cholesterol.
• Maintain a healthy weight: One study found that LDL cholesterol particles can become dysfunctional and less effective at delivering their cholesterol to various tissues due to obesity-related inflammation. Expression of LDL receptors also tends to be reduced among people with obesity. Fortunately, losing just 5 to 10 percent of body weight has been shown to lower total and LDL cholesterol, as well as triglycerides in people with overweight or obesity.

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