What are phospholipids and multivitamins?

What Are Phospholipids and Multivitamins?

Phospholipids

Phospholipids are essential structural components of all cell membranes that influence cellular function by affecting membrane protein activity, serving as precursors for signaling molecules, and modulating gene expression. 1

Structural and Functional Role

• Phospholipids contribute to the physicochemical properties of cell membranes and determine the conformation and function of membrane-bound proteins including receptors, ion channels, and transporters 1
• They serve as precursors for prostaglandins and other signaling molecules that regulate cellular processes 1
• The most commonly affected phospholipids in disease states are phosphatidylcholine, phosphatidylethanolamine, and sphingomyelin 2

Dietary Sources and Therapeutic Applications

• Common dietary sources include soy, egg yolk, milk, and marine products 1
• Phospholipids are highly effective in delivering their fatty acid residues for incorporation into cell membranes, which can influence immune function and cancer cell activity 1
• The fatty acid composition of the phospholipid determines its biological effect, making the type of phospholipid crucial for therapeutic outcomes 1

Clinical Applications

• Essential phospholipids have shown benefit in nonalcoholic fatty liver disease (NAFLD), with significant improvements in liver enzymes (mean ALT reduction of 50.8 IU and AST reduction of 46.1 IU) when used as adjuvant therapy 3
• Nutritional deficiencies affecting phospholipid metabolism include deficiencies in essential fatty acids, vitamins A and E, folate, zinc, and magnesium 2

Multivitamins

For the general healthy adult population, multivitamin supplementation shows insufficient evidence for cardiovascular disease or cancer prevention, and nutrients should primarily come from a diet rich in fruits, vegetables, whole grains, and low-fat dairy products rather than supplements. 4

Evidence-Based Recommendations from USPSTF

• The USPSTF found no effect on all-cause mortality in trials assessing multivitamin supplementation 4
• There is insufficient evidence to determine the balance of benefits and harms of multivitamin supplementation for preventing cardiovascular disease or cancer in healthy adults 4
• β-carotene and vitamin E supplements should be avoided for disease prevention, as β-carotene increases lung cancer risk in high-risk individuals (smokers and those with asbestos exposure) 4

Appropriate Use Cases

• Women planning pregnancy or who may become pregnant should receive daily folic acid supplementation to prevent neural tube defects 4
• Older persons at risk for falling should receive vitamin D supplements 4
• These recommendations apply to healthy adults aged 50 years or older and do not apply to children, pregnant women, chronically ill patients, or those with known nutritional deficiencies 4

Safety Profile

• Multivitamins at doses within the dietary reference intake range are safe for long-term use (more than 10 years) and do not increase mortality 5
• Only minor adverse effects (nonspecific gastrointestinal symptoms) have been reported, with no significant differences between treatment and placebo groups 5
• Important harms exist with excessive doses: moderate doses of vitamin A may reduce bone mineral density, while high doses can be hepatotoxic or teratogenic 4
• Vitamins A and D have known harms at doses exceeding tolerable upper intake levels 4

Clinical Pitfalls to Avoid

• Do not recommend multivitamins as a substitute for dietary improvement—adequate nutrition through food (fruits, vegetables, whole grains, fat-free and low-fat dairy, seafood) is associated with reduced cardiovascular disease and cancer risk 4
• Avoid β-carotene supplementation in smokers or those with occupational asbestos exposure due to increased lung cancer risk 4
• Be aware that commercial formulations vary considerably in content and concentration, making it difficult to extrapolate results from clinical trials to real-world use 4
• Consumers generally recognize that supplements should not replace healthy dietary habits (80% agreement in surveys), supporting their use only as gap-fillers rather than dietary replacements 6