What are the negative effects of palm oil on the body?

November 10, 2025 •

4 min read

Palm oil is found in an estimated 50% of all supermarket products, making its impact on human health a significant concern. The high concentration of saturated fats in palm oil, particularly palmitic acid, is linked to several potential negative effects on the body, including an increased risk of heart disease and inflammation.

Quick Summary

Consuming excessive amounts of palm oil, which is high in saturated fat, may increase LDL cholesterol, systemic inflammation, and contribute to weight gain. Processing methods and repeated heating amplify the risks.

Key Points

High Saturated Fat: Palm oil contains approximately 50% saturated fat, which can raise unhealthy LDL cholesterol levels.
Increased Heart Disease Risk: Higher LDL cholesterol is a primary risk factor for cardiovascular diseases, including coronary heart disease and stroke.
Promotes Inflammation: Excessive consumption, especially of repeatedly heated or processed palm oil, can trigger systemic inflammation in the body.
Carcinogenic Contaminants: Refining palm oil at high temperatures can create process contaminants like GE and 3-MCPD, which are potentially carcinogenic.
Contributes to Weight Gain: Its calorie density and high fat content can contribute to weight gain and obesity, exacerbating metabolic issues.
Oxidative Stress: Repeatedly heating palm oil increases lipid peroxidation and oxidative stress, which can cause cellular damage.
Unrefined vs. Refined: The refined version commonly found in processed foods poses greater health risks than the antioxidant-rich, unrefined red palm oil.

The Link Between Saturated Fat and Heart Health

One of the most significant concerns regarding palm oil is its high saturated fat content, which is approximately 50%. While this is lower than coconut oil, it is substantially higher than healthier options like olive oil. Saturated fat has long been associated with cardiovascular disease because it can raise low-density lipoprotein (LDL) or "bad" cholesterol levels in the blood.

A meta-analysis of clinical trials found that consuming palm oil significantly increased LDL cholesterol when compared to other vegetable oils that are lower in saturated fat. Elevated LDL cholesterol can lead to the build-up of plaque in arteries, a condition known as atherosclerosis, which can eventually result in coronary heart disease, stroke, and other cardiovascular problems. The primary culprit in palm oil is palmitic acid, a saturated fatty acid that makes up about 44% of its fat content.

The Role of Palm Oil in Inflammation and Oxidative Stress

Chronic inflammation is a contributing factor to many health issues, including heart disease and metabolic disorders. Research suggests that excessive palm oil consumption, particularly in highly processed or repeatedly heated forms, can exacerbate inflammatory responses within the body. Animal studies, for instance, have shown that repeatedly heated palm oil can increase inflammation, blood pressure, and cause vascular damage.

Repeated heating causes the oil to oxidize, creating harmful compounds and increasing oxidative stress. One study in rats found that those fed repeatedly heated palm oil had significantly increased lipid peroxidation and total cholesterol. Conversely, human studies on fresh, unheated palm oil often show more neutral effects on inflammatory markers, highlighting that processing and cooking methods play a critical role. However, the high palmitic acid content, even in fresh oil, can still promote inflammation and metabolic dysregulation, particularly when part of an unhealthy high-fat diet.

Potential Carcinogenic Contaminants from Refining

High-temperature processing, a common practice in producing refined palm oil for commercial use, can introduce potentially harmful contaminants. During this process, substances called 3-monochloropropane-1,2-diol (3-MCPD) and glycidyl fatty acid esters (GE) can form.

Glycidyl fatty acid esters (GE): The International Agency for Research on Cancer (IARC) classifies GE as "probably carcinogenic to humans".
3-monochloropropane-1,2-diol (3-MCPD): This substance is classified by the IARC as "possibly carcinogenic to humans".

Refined palm oil is used widely in processed snacks, fried foods, and baked goods. While unrefined red palm oil retains more beneficial antioxidants, its strong flavor limits its use, meaning most palm oil exposure comes from the refined version containing these concerning contaminants.

Weight Gain, Insulin Resistance, and Metabolic Effects

The caloric density of palm oil, coupled with its high saturated fat content, means that overconsumption can easily lead to weight gain. Animal studies have explored the metabolic impact of different palm oil forms. One study showed that interesterified palm oil, a processed form, promoted greater body weight gain and fat mass in mice compared to fresh palm oil. The study also linked these oils to increased lipogenesis (fat creation) and decreased beta-oxidation (fat burning), potentially leading to ectopic lipid accumulation in the liver and pancreas. This can contribute to conditions like hepatic steatosis (fatty liver) and insulin resistance.

Refined vs. Unrefined Palm Oil: A Comparison


Feature	Refined (Common) Palm Oil	Unrefined (Red) Palm Oil
Processing	Bleached, deodorized, and neutralized at high temperatures.	Minimally processed, retains natural color and nutrients.
Saturated Fat	High (approx. 50%).	High (approx. 50%).
Antioxidants	Reduced levels of vitamins A and E.	Rich in Vitamin E (tocotrienols) and beta-carotene.
Contaminants	Potential for carcinogenic process contaminants (3-MCPD, GE).	Lower risk of processing-related contaminants due to minimal heat.
Flavor/Odor	Neutral taste, lacks distinct odor.	Strong, distinct flavor and odor.
Common Use	Processed foods, baked goods, frying.	Health supplements, some traditional cooking.

Healthier Alternatives and Moderation

Given the potential negative effects of palm oil, especially refined versions, a balanced approach is crucial. Public health experts suggest that while palm oil is a better option than trans fats, it is not as healthy as liquid vegetable oils, such as olive oil or canola oil. These alternatives are significantly lower in saturated fat and higher in heart-healthy monounsaturated and polyunsaturated fats. Mindful consumption involves checking food labels for palm oil, often listed generically as "vegetable oil," and limiting intake of highly processed foods.

To learn more about healthy fats, you can read the resource from Harvard Health on Choosing healthy fats.

Conclusion

The potential negative effects of palm oil are directly linked to its high saturated fat content, particularly palmitic acid. When consumed in excess, this can raise bad cholesterol levels and increase the risk of heart disease. Furthermore, repeatedly heated and highly refined palm oil presents additional risks, including the formation of potentially carcinogenic compounds and increased inflammation. While unrefined red palm oil contains beneficial antioxidants, the vast majority of consumer exposure comes from the refined oil in processed foods. Ultimately, a move toward healthier, less saturated fat alternatives and moderation in overall fat intake is the most prudent path to mitigating these health risks.

Frequently Asked Questions

Yes, excessive consumption of palm oil can increase the risk of heart disease. It contains a high percentage of saturated fat, which has been shown in studies to increase LDL (bad) cholesterol, a major risk factor for cardiovascular disease.

Palm oil is often considered less healthy than vegetable oils low in saturated fats, such as olive or canola oil. However, it is generally healthier than trans fats and some animal-based fats. The overall impact depends on the comparison oil and consumption level.

Refined palm oil is processed at high temperatures, which removes its color, flavor, and much of its antioxidant content. Red palm oil is minimally processed, retaining its high levels of beta-carotene and vitamin E, giving it a strong flavor and reddish hue.

Yes, repeatedly heating palm oil is particularly harmful. This process increases oxidative stress and can lead to the formation of toxic by-products, which have been linked to increased inflammation and other adverse health effects in animal studies.

Yes, refined palm oil processed at high temperatures can form potentially carcinogenic compounds like glycidyl fatty acid esters (GE) and 3-MCPD. Exposure can be minimized by choosing less processed foods and using healthier oils for cooking.

Excessive saturated fat intake from palm oil can promote systemic inflammation. When processed or repeatedly heated, the oil can become oxidized, producing harmful compounds that increase the inflammatory response.

Palm oil is calorie-dense, and overconsumption can contribute to weight gain and obesity, particularly when it replaces healthier fats. Processed forms of palm oil have been linked to greater body fat accumulation and metabolic disturbances in animal studies.