During the European Days of the French Society of Cardiology (JESFC 2026), a session was dedicated to popular nutritional advice and their scientifically proven effects. The key takeaway: exercise caution and maintain nuance!
The Role of Omega-3 in Cardiovascular Health
Dr. François Paillard, a cardiologist at the cardiovascular prevention center of CHU Rennes, explored the actual role of omega-3 in cardiovascular prevention. Omega-3 fatty acids come in three types: ALA (found in flaxseeds, walnuts, chia seeds, and canola oil), EPA, and DHA (both primarily found in fatty fish and fish oils). These can be consumed through diet or supplementation.
“Nutritional intake of omega-3, with two servings of fish (including one fatty fish) per week, is associated with a moderate reduction in cardiovascular events and overall mortality,” states Dr. Paillard.
However, he notes that low supplementation (around 1 g/day) is ineffective for cardiovascular disease prevention, except in cases of complete absence of fish consumption in the diet. High-dose supplementation (between 2 and 4 g/day) shows positive results, with several randomized studies supporting high-dose EPA supplementation. This led to the 2025 ESC recommendations (level IIa) to consider omega-3 (EPA, 2 × 2 g per day) in combination with statins for high-risk patients with triglycerides between 1.5 and 5.6 mmol/L, despite statin treatment.
“Be cautious of the risk of atrial fibrillation: there is a U-shaped relationship between DHA and EPA intake and this risk,” warns Dr. Paillard. “The risk decreases with dietary intake but increases with high-dose supplementation.”
Keto Diet: Myths and Realities
The ketogenic, or low-carb diet, which allows unrestricted intake of fats, proteins, and total energy, dates back to 1972 under the name of Dr. Atkins’ diet. Criticized in JAMA as early as 1973, it has only one validated indication: drug-resistant epilepsy in children, according to a 2020 Cochrane meta-analysis.
Professor Claire Carette, a nutritionist and diabetologist at the European Hospital Georges-Pompidou in Paris, highlights that no randomized nutrition trial is double-blind, a limitation to keep in mind.
Reviewing the latest data on the ketogenic diet, she notes that it shows no difference in long-term weight loss compared to other diets and does not increase cardiovascular risk. However, the Mediterranean diet performs better in terms of blood sugar levels. She emphasizes that “the problem with all these diets is how people actually follow them over time: a decrease in adherence is consistently observed.”
The Atkins diet, in particular, leads to reduced fiber intake, with a potential increased risk of colon cancer, warranting monitoring.
Intermittent Fasting: A Closer Look
Intermittent fasting involves reducing the daily eating window in various ways. It has shown no benefits for weight loss or metabolic parameters in overweight/obese populations, according to studies published in JAMA Internal Medicine and the NEJM.
In diabetic patients, it may offer some cardiometabolic benefits and improve left ventricular ejection fraction. However, these results should be taken with caution due to the small number of patients and short study durations.
A 2024 NEJM review concluded that only the Mediterranean diet shows cardiovascular benefits, while the DASH diet is effective for hypertension. Importantly, “consider the increased risk of eating disorders with all restrictive diets,” reminds Professor Carette.
The Sugar Debate
Dr. Kévin Seyssel, a dietitian-nutritionist from Corbas, Lyon, is a fan of scientific popularization. At JESFC, he criticized “no sugar challenges” and influencers who demonize sugar. He reiterated simple recommendations: the WHO advises no more than 50 g of sugars per day on a 2,000 kcal diet, and ANSES recommends 30 g of fiber per day. Beyond these moderate guidelines, be wary of accusatory and guilt-inducing nutritional messages often based on… nothing!
No conflicts of interest were reported by the speakers.
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