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Review · Biochimie · 2020Conflicts declared

Vegetable lecithins and their effects on lipid metabolism

Robert C, Couëdelo L, Vaysse C, Michalski MC · Free full text

What it found

Vegetable lecithins, widely used as food emulsifiers, appear to have an overall beneficial effect on blood and liver fats, especially in people with high cholesterol.

Most of the evidence comes from animal studies, and data on lecithins other than soy are lacking.

What they found

Studies in people

Cholesterol lowering in patients

In people with primary hyperlipidemia, soybean phospholipid supplements significantly reduced blood cholesterol levels. In diabetic patients, a 2-month supplement of polyenylphosphatidylcholine purified from soybean lecithin raised HDL cholesterol and Apolipoprotein A-I levels. These cholesterol-lowering effects are mainly seen under dyslipidemic conditions and remain controversial in people with normal lipid levels.

Animal and lab studies

Liver fat reduction in animals

In rats, replacing 20% of dietary triglycerides with phosphatidylcholine reduced liver triglyceride accumulation by two thirds. This was linked to lower activity of enzymes involved in making new fatty acids and higher fat burning in the liver. Soy lecithin has also been associated with reduced liver and VLDL cholesterol in animal studies.

Fat absorption still unclear

Studies in rats have given conflicting results on whether dietary lecithin increases fat absorption. Some found no difference in lymphatic fat output when lecithin was added at low levels, while one study using a high dose of soybean phosphatidylcholine found increased fat absorption. The authors say the evidence remains inconclusive.

Obesity and metabolic health

In mice fed a high-fat diet, long-term soybean phosphatidylcholine supplementation reduced plasma triglycerides, cholesterol and leptin levels and lowered the LDL/HDL ratio. In rats, soybean lecithin supplements decreased food intake and gastric emptying, possibly by increasing a gut hormone called cholecystokinin. These effects have not been confirmed in people.

Studies in people and animals

Gut bacteria and TMAO

Gut bacteria can convert dietary phosphatidylcholine to trimethylamine, which the liver turns into trimethylamine N-oxide (TMAO). High TMAO levels in blood have been linked to higher risk of heart and metabolic disease. Recent research suggests this conversion depends on specific gut bacteria rather than just the amount of choline in the diet, and more research is needed.

Other findings

Composition varies by source

Vegetable lecithins contain more than 50% phospholipids and their fatty acid makeup reflects the oil seed they come from. Rapeseed lecithin is high in monounsaturated fats, while soy lecithin is high in polyunsaturated fats. The composition can vary more within one source due to crop and processing conditions than between different sources.

What the authors conclude

“Despite the lack of converging evidence concerning their effects on lipid digestion and intestinal absorption, it is clear that dietary vegetable lecithin exert an overall beneficial effect on lipid and lipoprotein metabolism.”
Robert C, Couëdelo L, Vaysse C, Michalski MC, 2020

Also in their conclusions

  • They conclude that dietary vegetable lecithin exerts an overall beneficial effect on lipid and lipoprotein metabolism, despite conflicting evidence on digestion and absorption.
  • They propose vegetable lecithins as potential novel therapeutic agents for treating hyperlipidaemia associated with metabolic and cardiovascular diseases.
  • They call for more research on lecithins from sources other than soybean and on how individual fatty acids and phospholipids affect lipid metabolism, intestinal integrity, low-grade inflammation and gut microbiota.

How it was done

The authors wanted to gather and summarise the existing research on how vegetable lecithins affect fat digestion, absorption and metabolism, and their potential role in preventing metabolic disorders. They note that demand for vegetable products is growing and their nutritional and bioactive properties need to be known.

The authors reviewed published studies on vegetable lecithins, including their composition, how they are digested and absorbed, and their effects on blood and liver fats. The studies covered people, animals and lab tests, and looked at lecithins from soy, sunflower, rapeseed and other vegetable sources.

What it can’t tell you

  • Most of the evidence on cholesterol and liver fat comes from animal studies, so it cannot show what happens in people.
  • The studies in people mainly involved patients with existing high cholesterol or diabetes, so the findings may not apply to healthy people.
  • The review cannot show cause and effect because it summarises different types of studies, including some that only observe links.

The paper

Title
Vegetable lecithins: A review of their compositional diversity, impact on lipid metabolism and potential in cardiometabolic disease prevention
Type
ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
Evidence
Studies in people · animals · lab
Summarised from
Full text
Licence
CC BY. Words in quotation marks are the authors’; the rest is our summary.
Cite
Robert C, Couëdelo L, Vaysse C, Michalski MC (2020). Vegetable lecithins: A review of their compositional diversity, impact on lipid metabolism and potential in cardiometabolic disease prevention. Biochimie. doi:10.1016/j.biochi.2019.11.017Free full textPubMed 31786232DOI

Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error