The key facts
- The meta-analysis covered 48 studies, 2,719 participants with cardiovascular disease or hypertension, and 31 dietary interventions
- Statistically significant reductions in arterial stiffness were shown for grape seed extract and folic acid (vitamin B9)
- The authors emphasize: the results do not prove prevention of heart attacks and strokes; further research is needed
What the Studies Showed
Grape seed extract and vitamin B9 (folic acid) may help reduce arterial stiffness — an indicator closely linked to the risk of cardiovascular disease. This is the conclusion reached by researchers from Bushehr University of Medical Sciences; the results of the work were published in the journal Food & Function.
Scale of the Analysis
The scientists analyzed 48 clinical trials involving 2,719 people suffering from cardiovascular disease or arterial hypertension. In total, the specialists compared 31 dietary interventions, including vitamins, plant extracts, and other dietary supplements.
Method and Results
The main indicator was pulse wave velocity — a method for assessing arterial stiffness. After taking grape seed extract and folic acid, this indicator decreased statistically significantly compared with placebo. Some other substances, including alpha-linolenic acid, dietary nitrates, and wine extract, also showed positive changes in individual indicators, but the results did not reach statistical significance.
Why Vascular Stiffness Matters
Healthy arteries are elastic and expand and contract in response to changes in pressure. With age, as well as with hypertension and certain metabolic disorders, vessel walls may become less compliant. As a result, the heart has to work harder, and the risk of cardiovascular complications may increase.
Mechanisms of Action
Grape seed extract contains polyphenols, including proanthocyanidins, which are studied for their potential effects on oxidative processes and the function of the vascular endothelium — the inner layer of blood vessels. Folic acid may affect vascular condition, in particular through the regulation of homocysteine levels.
Limitations of the Conclusions
The results of the meta-analysis do not mean that these supplements reliably prevent heart attacks or strokes. According to the scientists, additional studies are needed to confirm the long-term benefits.
