What is nutrition, and what role does it play in preventive health?
Nutrition is the science that studies the interactions between food and the body—from ingestion through to cellular utilization. According to the WHO, noncommunicable diseases (cardiovascular diseases, type 2 diabetes, cancers, obesity) account for 74% of global deaths, and a significant proportion of these is directly linked to unhealthy dietary habits. Large epidemiological studies—EPIC (500,000 participants), SU.VI.MAX, and PREDIMED—have helped quantify risks and identify protective nutrients: omega-3, vitamin D, and polyphenols.
What is the NOVA classification and why is it important?
The NOVA classification, developed by Carlos Monteiro, categorizes foods into four groups based on their degree of industrial processing:
- Group 1: unprocessed or minimally processed foods (fruits, vegetables, eggs, fresh meats, legumes).
- Group 2: processed culinary ingredients (oils, salt, sugar, flour).
- Group 3: processed foods (canned goods, aged cheeses, artisanal deli meats).
- Group 4: ultra-processed foods (UPFs)—contain additives not found in common culinary preparations. Prospective studies link them to an increased risk of cardiovascular disease (+12% for every 10% of total energy intake from UTPs), type 2 diabetes (+15%), and all-cause mortality.
Which nutrients play a key role in preventive nutrition?
Research identifies several nutrients with a strong preventive impact:
- Vitamin D3: modulates the expression of more than 200 genes involved in immunity, cell proliferation, and bone mineralization. Vitamin D3 deficiency is associated with an increased risk of autoimmune diseases, infections, and certain cancers.
- Resveratrol: a polyphenol found in red grapes that activates sirtuins (SIRT1)—proteins that regulate cellular aging—and inhibits pro-inflammatory pathways.
- Selenium: a cofactor for glutathione peroxidase and thioredoxin reductase, two antioxidant enzymes that protect DNA from oxidative damage. A deficiency in selenium is associated with an increased risk of certain cancers.
What is the role of the microbiota in nutrition and health?
The gut microbiota—38 trillion microorganisms in the colon—is now considered a full-fledged organ with metabolic, immune, and neurological functions:
- Fermentation of indigestible fiber → production of butyrate, propionate, and acetate (short-chain fatty acids) that nourish colonocytes, regulate blood sugar levels, and reduce systemic inflammation.
- Synthesis of vitamin K2 and certain B vitamins by gut bacteria.
- Regulation of the gut-brain axis: 95% of the body’s serotonin is produced in the gut, under the direct influence of the microbiota.
Probiotics as dietary supplements can specifically modulate the microbiota for targeted conditions (post-antibiotic dysbiosis, irritable bowel syndrome, respiratory infections).
What is nutritional chronobiology?
Nutritional chronobiology studies the impact of mealtime on metabolism:
- Insulin sensitivity is highest in the morning and gradually decreases—the same carbohydrates produce a blood sugar spike that is 50% higher in the evening than in the morning.
- A hearty breakfast and a light dinner (time-restricted eating aligned with the circadian rhythm) improve blood glucose levels, triglycerides, and body weight compared to the reverse pattern.
- Eating more than 3 hours before bedtime improves sleep quality and reduces nighttime production of VLDL (precursors to LDL).
How do supplements fit into a nutritional approach?
Dietary supplements are not a substitute for a balanced diet but can address specific deficiencies:
- Vitamin D3 and omega-3s: the two nutrients most commonly deficient in the French population, with strong evidence supporting their role in cardiovascular, bone, and immune health.
- Standardized turmeric (curcuminoids + piperine): an anti-inflammatory compound whose low bioavailability from food justifies supplementation to achieve measurable therapeutic effects.
- Selenium and zinc: Their content in foods depends heavily on soil quality—targeted supplements correct deficiencies that are difficult to address through diet alone, depending on the region.
