Mayonnaise is not inherently good or bad for cholesterol. Its effect depends almost entirely on the type of oil used as its base, how much saturated fat it delivers, and how much you eat. A tablespoon of standard mayonnaise contains only a few milligrams of cholesterol from egg yolk, which turns out to matter far less than the fat profile of the oil surrounding it. The story is more nuanced than the old “eggs are bad” narrative suggested, and some reformulated versions of mayonnaise can actually work in favor of your lipid numbers.
What in Mayonnaise Actually Affects Your Cholesterol
Mayonnaise is an emulsion of oil, egg yolk, and acid (usually vinegar or lemon juice). Oil typically makes up anywhere from 65 to 80 percent of a full-fat jar, which means the dominant fat in that oil is what shapes the product’s cholesterol impact. Egg yolk contributes dietary cholesterol and lecithin, but by volume it is a minor player compared to the oil.
Three components deserve separate attention when it comes to blood lipids: the saturated fat content of the oil, the dietary cholesterol from egg yolk, and the lecithin in the yolk that feeds a gut-bacteria pathway linked to cardiovascular risk. Each of these influences cholesterol through a different mechanism, and they do not all push in the same direction.
Why the Oil Matters More Than the Yolk
Most commercial mayonnaise sold in the United States is made with soybean oil, which is relatively high in polyunsaturated fat and low in saturated fat. Clinical evidence shows that when soybean oil replaces dietary saturated fat, blood cholesterol levels drop.1PubMed. Soybean oil lowers circulating cholesterol levels and coronary heart disease risk, and has no effect on markers of inflammation and oxidation That is a meaningful distinction, because not all mayonnaise around the world uses the same oil. Some brands and homemade recipes use palm oil, coconut oil, or blends with a higher saturated fat load.
A randomized crossover trial directly compared mayonnaise made from soybean oil against mayonnaise made from palm olein. The soybean-oil version lowered total cholesterol by about 0.25 mmol/L and LDL cholesterol by about 0.17 mmol/L compared to the palm-olein version. HDL cholesterol also dipped slightly with soybean oil, but the LDL-to-HDL ratio stayed the same between the two.2Lipids in Health and Disease. Comparing effects of soybean oil- and palm olein-based mayonnaise consumption on the plasma lipid and lipoprotein profiles in human subjects: a double-blind randomized controlled trial with cross-over design So two jars sitting on the same shelf can have opposite effects on your lipid panel depending on the oil listed on the back label.
The mechanism behind this is well established. Saturated fat reduces the number of LDL receptors in the liver, which are the proteins responsible for pulling LDL particles out of the bloodstream. When people ate a low-saturated-fat diet, their LDL receptor activity increased by about 10 percent, and their LDL cholesterol fell by roughly 12 percent. The two changes tracked in near lockstep.3Journal of Lipid Research. Dietary saturated fat regulation of hepatic low density lipoprotein receptor abundance in humans If your mayonnaise is made with a high-saturated-fat oil, you are nudging that receptor system in the wrong direction every time you spread it on a sandwich.
The Egg Yolk and Dietary Cholesterol
For decades, health authorities warned people to limit dietary cholesterol to under 300 milligrams a day, which put eggs and egg-containing foods like mayonnaise on the caution list. That position has softened considerably. In 2015, dietary cholesterol restrictions were dropped by most health agencies worldwide and recommended to be removed from the U.S. Dietary Guidelines.4PubMed Central. The Fifty Year Rehabilitation of the Egg
The shift happened because research kept showing that for most people, eating cholesterol does not reliably raise blood cholesterol in a clinically meaningful way. A recent randomized crossover study found that dietary cholesterol intake was not correlated with LDL cholesterol levels, whereas saturated fat intake was. Across all diets in that study, every additional gram of saturated fat predicted higher LDL, but the amount of cholesterol in the food did not.5PubMed. Impact of dietary cholesterol from eggs and saturated fat on LDL cholesterol levels: a randomized cross-over study This lines up with what has been emerging for years: the cholesterol you eat is a weaker lever on your blood cholesterol than the type of fat you eat alongside it.
That said, egg consumption is not completely neutral. A meta-analysis of 17 randomized controlled trials found that people who ate more eggs did have somewhat higher LDL cholesterol and a slightly worse LDL-to-HDL ratio compared to control groups. The effect was small but statistically significant, and it grew somewhat stronger in studies lasting more than two months.6PubMed Central. Association between Egg Consumption and Cholesterol Concentration: A Systematic Review and Meta-Analysis of Randomized Controlled Trials Since a tablespoon of mayonnaise contains only a fraction of one egg yolk, the contribution from the condiment itself is modest. But if you are someone who eats eggs at breakfast, mayonnaise at lunch, and baked goods made with eggs at dinner, it adds up.
Your Genes Change the Equation
Not everyone responds to dietary cholesterol the same way. About a quarter of the population carries at least one copy of the ApoE4 gene variant, which changes how the body handles cholesterol from food. In a large Finnish cohort study, egg intake was associated with a generally more favorable lipid profile in people who did not carry ApoE4, including a better total-to-HDL-cholesterol ratio and a better LDL-to-HDL ratio. Among ApoE4 carriers, those favorable associations vanished.7The American Journal of Clinical Nutrition. Associations of egg and cholesterol intakes with carotid intima-media thickness and risk of incident coronary artery disease according to apolipoprotein E phenotype in men: the Kuopio Ischaemic Heart Disease Risk Factor Study
This does not mean ApoE4 carriers saw their cholesterol spike from eggs. The study found no significant link between egg or cholesterol intake and coronary artery disease risk in either group. But the fact that the lipid-profile improvements seen in non-carriers simply did not appear in carriers suggests the two groups process dietary cholesterol differently. If you have had genetic testing and know you carry ApoE4, it is reasonable to be a little more cautious about concentrated sources of dietary cholesterol, including whole-egg mayonnaise.
The TMAO Angle
There is a less well-known pathway that connects egg-based foods to cardiovascular risk without going through LDL cholesterol at all. Egg yolk is rich in phosphatidylcholine, a form of lecithin. When you eat it, gut bacteria metabolize the choline into trimethylamine, which the liver then converts to trimethylamine N-oxide, or TMAO. Elevated TMAO levels have been associated with a substantially higher risk of major cardiovascular events. In one study, people in the highest quartile of plasma TMAO had about two and a half times the risk of a heart attack, stroke, or cardiovascular death compared to those in the lowest quartile.8PubMed Central. Intestinal microbial metabolism of phosphatidylcholine and cardiovascular risk
How much this matters for a condiment-sized serving of mayonnaise is genuinely unclear. The TMAO research is based on dietary phosphatidylcholine challenges, not specifically on mayonnaise intake. A tablespoon of mayo contains far less lecithin than a full egg. Still, if you are someone who consumes a lot of choline-rich foods daily, the TMAO pathway is worth knowing about, because it is a route by which egg-based products could affect cardiovascular risk even if your LDL number looks fine.
Cholesterol Oxidation During Storage
One concern that rarely makes it into popular health advice is what happens to the cholesterol already present in mayonnaise as the jar sits in your fridge. Cholesterol can oxidize into compounds called cholesterol oxidation products, and these oxidized forms are thought to be more atherogenic than plain cholesterol. In stored mayonnaise, cholesterol oxidation products appeared within about 15 days of manufacture and kept increasing over months. After 165 days, the total concentration reached about 20 micrograms per gram when stored at refrigerator temperature and about 30 micrograms per gram when stored at room temperature.9Food Chemistry. Oxidation of cholesterol in mayonnaise during storage
The practical takeaway is simple: keep mayonnaise refrigerated and use it within a reasonable timeframe. A jar left out on the counter or kept for months past opening is accumulating more oxidized cholesterol than one used promptly and stored cold. This is not a reason to panic about a fresh jar, but it is a reason not to treat the expiration date as a suggestion.
Trans Fats and the Historical Problem
For much of the twentieth century, partially hydrogenated vegetable oil was a common ingredient in processed foods, including some commercial mayonnaises and salad dressings. These oils were the primary source of artificial trans fat in the American diet.10PubMed Central. The Demise of Artificial Trans Fat: A History of a Public Health Achievement Trans fats are uniquely bad for cholesterol because they simultaneously raise LDL and lower HDL, a double hit that no other dietary fat delivers as reliably.
The good news is that this concern is largely historical. The U.S. Food and Drug Administration finalized a determination in 2015 that partially hydrogenated oils are not “generally recognized as safe,” and the phase-out was completed by 2020. Most mayonnaise on store shelves today contains no trans fat. If you are buying a mainstream brand in the U.S. or Europe, this is not something you need to check for. If you are buying imported brands, artisanal products, or older stock, a glance at the ingredients list for “partially hydrogenated” is still worthwhile.
Reduced-Fat and Reformulated Options
If you want the flavor of mayonnaise without the full cholesterol and fat load, the food industry has been working on that for years. One approach substitutes part of the egg yolk with soybean oil body, a protein-lipid extract from soybeans. When half the egg yolk was replaced this way, the cholesterol content of the mayonnaise dropped from about 124 milligrams per 100 grams to about 48 milligrams, and fat content fell from about 53 percent to 44 percent.11LWT. Low-cholesterol-low-fat mayonnaise prepared from soybean oil body as a substitute for egg yolk That is a significant reduction from an ingredient swap that does not change the basic character of the product.
Another approach goes a step further by adding plant sterols, also called phytosterols, which actively compete with cholesterol for absorption in the gut. Phytosterol-enriched mayonnaise-type dressings have been developed specifically for people who are already watching their cholesterol. The logic is that someone choosing low-fat condiments is exactly the person most likely to benefit from a cholesterol-lowering ingredient baked into the product.12PubMed Central. Property of Phytosterols and Development of Its Containing Mayonnaise-Type Dressing These products are more common in some markets than others, but if you see phytosterols on a mayonnaise label, that is a functional ingredient with a genuine cholesterol-lowering track record.
Avocado-oil and olive-oil mayonnaises sit somewhere in between. They are higher in monounsaturated fat than standard soybean-oil versions, which is generally considered favorable for heart health. They do not eliminate the egg yolk or its cholesterol, but they shift the overall fat profile in a direction most dietary guidelines endorse. The caveat is that “made with avocado oil” on the front label does not always mean avocado oil is the primary fat. Read the ingredients list to see whether soybean or canola oil is listed first.
Sodium as a Side Concern
Cholesterol tends to dominate conversations about mayonnaise and heart health, but sodium is worth a mention because it affects the same cardiovascular system through a different route. A typical serving of mayonnaise contains a moderate amount of sodium, and researchers have shown that encapsulated flavor compounds can allow salt reductions of up to 50 percent in mayonnaise without wrecking the taste, bringing it in line with reduced-sodium nutrition claims.13Frontiers in Nutrition. The influence of salt reduction with encapsulated oleoresins on the quality of mayonnaise, mustard, and ketchup For most people, a tablespoon of mayo is not a major sodium contributor compared to bread, cheese, or deli meat in the same sandwich. But if you are on a sodium-restricted diet, choosing a reduced-sodium version or simply using less addresses the concern without needing to eliminate the condiment entirely.
How LDL Particle Size Fits In
One wrinkle that comes up in cholesterol discussions is that not all LDL particles are created equal. Smaller, denser LDL particles are generally considered more atherogenic than larger, more buoyant ones. The soybean-versus-palm-olein mayonnaise trial found that the palm olein version increased large LDL particles, while small LDL particles stayed the same between the two oils.2Lipids in Health and Disease. Comparing effects of soybean oil- and palm olein-based mayonnaise consumption on the plasma lipid and lipoprotein profiles in human subjects: a double-blind randomized controlled trial with cross-over design Separately, the egg-and-saturated-fat crossover study found that an egg-containing diet increased small LDL particles while reducing large ones, compared to a control diet.5PubMed. Impact of dietary cholesterol from eggs and saturated fat on LDL cholesterol levels: a randomized cross-over study
The particle-size story is complex and still evolving, but the practical implication is that looking only at your total LDL number can miss some of the picture. Two people with the same LDL on a standard blood test might have very different cardiovascular risk profiles depending on the size distribution of their particles. The type of fat in your mayonnaise feeds into that distribution, which is another reason the oil choice matters.
Practical Choices at the Grocery Store
If you are actively managing your cholesterol and wondering whether to keep mayonnaise in your diet, a few concrete steps help more than any blanket “good” or “bad” label:
- Check the oil: Soybean, canola, or avocado oil as the first ingredient is a better starting point than palm or coconut oil. The oil is the dominant fat source and the biggest single lever on your lipid panel.
- Watch serving size: Most nutrition labels list a serving as one tablespoon. People regularly use two or three times that on a sandwich without thinking about it. The modest cholesterol and fat numbers on the label scale up fast.
- Consider reduced-fat versions: Products that substitute part of the egg yolk with plant-based emulsifiers can meaningfully cut cholesterol content while keeping the texture recognizable.
- Store it cold: Refrigeration slows the oxidation of the cholesterol already in the jar, which keeps the product in its least harmful form.
- Look at the whole meal: A tablespoon of mayonnaise on a salad full of vegetables is a different dietary context than mayonnaise on a triple-decker club sandwich with bacon and cheese. The condiment rarely acts alone.
The evidence does not support treating mayonnaise as a cholesterol villain. It also does not support treating it as a health food. Where it lands for you depends on which version you buy, how much you use, what else you eat it with, and, to a degree science is still mapping out, which genetic hand you were dealt.