A 2003 Framingham study found that older adults with higher blood homocysteine levels were more likely to develop heart failure. The study did not show that cholesterol was irrelevant, and it did not test whether B vitamins prevent heart attacks. Its actual outcome was new heart failure, a condition in which the heart cannot pump enough blood for the body's needs.
The earlier version of this article described that study as evidence about first heart attacks and told readers to take B vitamins instead of cholesterol-lowering medicine. Both claims needed correction. The original paper is Plasma homocysteine and risk for congestive heart failure in adults without prior myocardial infarction.
What the Framingham researchers found
The researchers followed 2,491 adults in the Framingham Heart Study. Their average age was 72, and none had heart failure or a prior heart attack at the start. Blood homocysteine was measured, and the team looked for a first episode of heart failure over eight years. During follow-up, 156 participants developed heart failure.
After accounting for other known risk factors, people whose homocysteine was above the median for their sex had a higher rate of heart failure. The estimated risk was about 1.9 times as high in women and 1.8 times as high in men. That is an association. The study did not randomly assign people to have higher or lower homocysteine, so it cannot establish that homocysteine itself caused the heart failure. It also cannot establish that lowering homocysteine would prevent it.
Homocysteine is a substance the body makes while processing methionine, an amino acid found in protein. Folate, vitamin B12, and vitamin B6 take part in pathways that process it. A high reading can reflect several things, including nutrient status and kidney function. Measuring a marker and treating the cause of disease are separate questions.
Did lowering homocysteine prevent cardiovascular events?
Later randomized trials tested the proposed treatment more directly. In the HOPE-2 trial, 5,522 people with vascular disease or diabetes received either folic acid, B6, and B12 or a placebo for an average of five years. The vitamins lowered homocysteine, but the main combined outcome of cardiovascular death, heart attack, or stroke occurred in 18.8% of the vitamin group and 19.8% of the placebo group. That difference was not statistically significant. The trial is Homocysteine lowering with folic acid and B vitamins in vascular disease.
HOPE-2 reported fewer strokes in the vitamin group as a secondary finding. That does not change the null result for the main outcome, and it does not support replacing established heart treatment with B vitamins. Another trial in people who had already had a heart attack also found that B-vitamin treatment did not lower recurrent cardiovascular risk (Homocysteine lowering and cardiovascular events after acute myocardial infarction).
These trials studied specific doses and groups of patients. They do not mean that folate or B12 deficiency should go untreated. They show that lowering a blood marker with supplements does not automatically prevent the disease associated with that marker. High-dose B6 also has potential harms: long-term supplement use can cause nerve damage. The NIH vitamin B6 fact sheet explains the safety limits and symptoms to watch for.
What the cholesterol trials show
LDL cholesterol is carried in particles that can enter artery walls and contribute to plaque. A person's LDL level is one part of cardiovascular risk, alongside age, blood pressure, smoking, diabetes, and previous disease. A treatment decision should consider the person's overall risk and preferences, not a slogan about one blood test.
Unlike the proposed B-vitamin substitution, LDL-lowering treatment has repeatedly been tested against real clinical outcomes. The Heart Protection Study randomly assigned 20,536 people at high cardiovascular risk to simvastatin or placebo for about five years. Major vascular events occurred in 19.8% of those assigned simvastatin and 25.2% of those assigned placebo. Deaths from any cause were 12.9% versus 14.7%. Those are patient outcomes, not just improved cholesterol numbers (MRC/BHF Heart Protection Study).
Other approaches to lowering LDL have also improved outcomes in selected high-risk groups. After a recent acute coronary event, adding ezetimibe to a statin produced a modest reduction in a combined cardiovascular outcome compared with a statin alone (IMPROVE-IT trial). In people with established cardiovascular disease already taking statins, the PCSK9 inhibitor evolocumab reduced major cardiovascular events compared with placebo (FOURIER trial). These drugs have different effects and costs, and they are not interchangeable for everyone. Together, the trials refute the claim that lowering LDL has no clinical value.
How to use this information
Homocysteine may still matter in research and in the evaluation of particular medical conditions. The Framingham finding remains interesting, but it cannot be used as evidence that statins are useless or that B vitamins are a substitute. Cholesterol treatment also has potential side effects and a person's expected benefit depends on their starting risk. Those are reasons for a careful discussion with a clinician, not for abruptly stopping a prescribed medicine.
Food, physical activity, blood-pressure care, and smoking avoidance also matter to heart health. Our beetroot and blood-vessel study review shows how a change in a short-term marker differs from proof that an intervention prevents heart attacks. When weighing any heart-health claim, check what researchers actually measured and whether a randomized trial found fewer illnesses or deaths.
