Protein and cholesterol differences
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Protein Type and Cholesterol Levels: Animal vs. Plant Protein
Research consistently shows that the type of dietary protein—animal or plant—can have significant effects on cholesterol levels. Animal proteins, especially casein, tend to increase plasma total cholesterol compared to plant proteins like soy, pea, rice, and potato proteins, which generally lower cholesterol levels in both animal and human studies 1245679. Meta-analyses and intervention trials in people with high cholesterol confirm that replacing animal protein with plant protein leads to reductions in total cholesterol, LDL cholesterol, triglycerides, and improvements in HDL cholesterol, without significant effects on body weight or BMI 25.
Mechanisms: How Protein Source Affects Cholesterol
The cholesterol-lowering effect of plant proteins is linked to several mechanisms. One hypothesis is that animal proteins, which are higher in phosphorylated amino acids, may interfere with bile acid reabsorption, leading to higher cholesterol levels. Another theory suggests that the amino acid composition of proteins affects cholesterol absorption, storage, synthesis, and excretion 16. Plant proteins, especially those with lower methionine content, are associated with increased fecal steroid (bile acid and neutral steroid) excretion, which correlates with lower serum cholesterol . Additionally, plant proteins can alter gut microbiota, which in turn influences cholesterol metabolism; for example, pea protein increases beneficial bacteria that help lower cholesterol, while pork protein has the opposite effect .
Specific Protein Sources: Soy, Fish, and Others
Soy protein is particularly well-studied and has been shown to lower LDL and total cholesterol in adults by about 3-4% compared to non-soy proteins . Fish protein hydrolysate also reduces total cholesterol and increases the proportion of HDL cholesterol, with effects similar to soy protein but possibly through different mechanisms . Other plant proteins, such as those from rice and potato, also lower cholesterol, likely due to their low methionine content .
Protein Intake and Cardiometabolic Health
Higher overall protein intake, regardless of source, is associated with higher HDL cholesterol and lower BMI and waist circumference in adults, suggesting a potential benefit for cardiometabolic health . However, the source of protein remains important for cholesterol management, with plant proteins offering more favorable effects on lipid profiles.
Protein Modifications and Cholesterol Absorption
Some forms of plant protein, such as soy protein hydrolysate with bound phospholipids, can further decrease cholesterol absorption by reducing micellar solubility of cholesterol and increasing bile acid binding, leading to greater fecal excretion of cholesterol and lower serum cholesterol .
Conclusion
In summary, plant proteins—especially soy, pea, rice, and potato—consistently lower total and LDL cholesterol compared to animal proteins like casein and pork. These effects are mediated by differences in amino acid composition, effects on bile acid metabolism, and changes in gut microbiota. Choosing plant proteins over animal proteins can be an effective dietary strategy for improving cholesterol levels and supporting heart health 124567910.
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