New Study on Cardiovascular Risk

Debate about food and health is never-ending, as different diets, theories and speculation abound. The only way to test hypotheses is to study them rigorously.

The study of fats and health – in particular saturated fats – is currently much in the news as what-we-thought-we-knew is being challenged by recent research. A new collaborative study, known as the European Prospective Investigation into Cancer and Nutrition – Cardiovascular Disease (EPIC-CVD), aims to bring clarity to this debate.

Why do this study now? Because important questions need to be cleared up.

While nutrition is considered a cornerstone of reducing cardiovascular risk, the quantity and quality of various whole food and nutrient groups are still being debated. This is of particular relevance to fatty acids, with previously-held theories now being challenged.

The supposedly unfavourable role of total dietary saturated fatty acids, and the claimed beneficial role of omega-3 fatty acids on coronary heart disease (CHD) and cerebrovascular outcomes, have both been questioned by recent research. However, interpretation from dietary studies has been complicated by a number of problems:

1. There is potential misclassification in the questionnaires used to assess fatty acid consumption, which also lack the ability to reliably compute intake of specific fatty acids.
2. Recent epidemiological evidence indicates that, when individual fatty acids are examined, associations between specific fatty acid subtypes and disease risk may vary importantly within each family of fatty acid group considered.

In this respect, biomarkers (for example, circulating plasma fatty acids) may provide a more accurate assessment of consumption, instead of questionnaires.

Although several studies have examined the associations between circulating blood fatty acids and CHD risk – including one that my colleagues and I conducted and which was published in the Annals of Internal Medicine in 2014 – they were importantly limited by some critical factors:

• Inadequate power to investigate both composite and individual fatty acids
• Involving populations with diverse baseline health
• Inadequate adjustments for potential confounding (or mediating) factors
• Inability to characterise the shape of any dose-response relationship
• Insufficient detail to enable reliable assessment of the nature of any independent association with CHD across various individual characteristics
• Use of varying fatty acid assay methods or lipid fraction

What does this mean in practice? It means we need to do further study – with more real people, in real-life situations – that is properly monitored. This is how we can help to resolve the existing scientific uncertainties around saturated fats.

This should be undertaken as a comprehensive assessment of the relationship between total and individual fatty acids with subsequent incident CHD risk in a large, free-living general population.