Nutrition

Key Points

Our everyday diet doesn’t always meet our micronutrient needs — and large population studies in France and worldwide confirm this. However, it is possible to optimize our intake.

Food provides vitamins, minerals, amino acids, fatty acids, and many other substances in varying amounts. How much we absorb depends on our eating habits, food production methods, calorie intake, protein intake, age, and overall health. For instance, as we age, our bodies absorb certain B vitamins less efficiently. Chronic stress, on the other hand, can increase magnesium requirements.

Vitamins and minerals play a wide variety of essential biological roles. Deficiencies can lead to acute health problems, ranging from skin ulcers to depression. Over the long term, they may contribute to the development of chronic and degenerative diseases.

What Are the Vitamin and Mineral Requirements?

Each country’s health authorities set recommended nutrient intakes for different population groups: men, women, children, adolescents, and adults. In France, what used to be called “recommended dietary allowances” (ANC) are now referred to as the “Population Nutrient Reference” (RNP). The RNP is calculated to theoretically meet the needs of 97.5% of a given population — that is, almost everyone. It is estimated based on the average nutritional need (BNM) for a given nutrient.

For example, the BNM for vitamin A in women aged 18 and over is set at 490 μg retinol equivalent per day, while the RNP is set at 650 μg per day.

When the BNM and RNP cannot be reliably calculated due to lack of data, the concept of “satisfactory intake” (AS) is used instead. AS corresponds to the average intake observed in a population or subgroup with adequate nutritional status. For instance, the AS for selenium in adults is 70 μg/day.

For the official reference values in France, visit the ANSES website.

Is a “Varied and Balanced” Diet Enough?

Health authorities maintain that a varied and balanced diet should meet nutrient needs. However, technological advances, mechanization, reduced working hours, and the widespread use of household appliances have led to a sharp drop in physical activity — and, as a result, calorie intake has decreased. Fewer calories also means fewer vitamins and minerals.

A French study showed that with today’s lower calorie intakes, it is difficult to meet even 80% of the recommended levels for most vitamins.

Furthermore, even before industrial processing, the nutritional quality of food is often compromised by modern farming practices — the use of herbicides and pesticides, early harvesting, and storage all reduce the vitamin content of plants. As for ultra-processed foods — now the majority of supermarket offerings — they are naturally low in vitamins and minerals. Some are artificially enriched, but often more for marketing purposes than genuine nutritional benefit.

In short: our diets do not always provide sufficient vitamins and minerals.

In 1999, French researcher Nicole Darmon (INRAE, Montpellier) used linear programming to determine whether the typical French diet could meet the 1992 nutrient recommendations. Her conclusion: “Whether for men, women, or young children, it is simply impossible to construct a diet that meets the RNP without exceeding the quantities of food actually consumed by 50% to 75% of the population.”
The most challenging nutrients were vitamins B1, B6, E, D, and minerals like magnesium, iron, zinc, and copper.

What Are the Risks of Vitamin and Mineral Deficiencies in France?

Several large-scale dietary and epidemiological studies have assessed French people’s vitamin and mineral intakes and blood nutrient levels. Together, these studies show that nutritional needs are often unmet.

If you compare actual intakes to RNPs, significant portions of the population fall short. Even when adjusting the benchmarks — using 2/3 or even 1/2 of the RNP as indicators of high risk — the situation remains concerning.

Here’s a summary for some key nutrients:

• Vitamin B1:
  • 20–25% of adults consume less than half the ANC.
  • Biological signs of deficiency found in ~20% of adults, and up to 50% of young women (18–29 years).
• Vitamin B2:
  • Over one-third of people have intakes between 50–80% of ANC.
  • 14–31% of women show biological signs of deficiency.
• Vitamin B6:
  • 16% of men and 36% of women consume less than 2/3 of the ANC.
  • Biological deficiencies found in 15–20% of adults, and clear signs of clinical deficiency in 16%.
• Vitamin C:
  • About 1 in 5 adults consume less than 2/3 of ANC.
  • 20% of men show low blood vitamin C levels.
• Vitamin D:
  • In winter, average intake is just 3.4 μg/day — far below recommendations.
  • 80% of French adults are vitamin D deficient.
• Vitamin E:
  • 20% of men and 38% of women have low intakes.
  • 10–22% of adults show signs of moderate deficiency.
• Magnesium:
  • 23% of men and 18% of women fall below 2/3 of ANC.
  • Blood levels aren’t always reliable indicators.
• Iron (in women):
  • 45% of women have inadequate intakes.
  • 23% of women have insufficient iron stores.
• Zinc:
  • 25–79% of adolescents and women have intakes below 2/3 of ANC.
  • 5–8% show biological deficiency.

Omnivores and Vegetarians Both at Risk of Deficiencies

A systematic review of studies (2000–2020) comparing plant-based eaters and meat-eaters found that vegetarians and vegans have lower intakes and blood levels of vitamin B12, vitamin D, iron, zinc, iodine, calcium, and long-chain omega-3s (EPA, DHA).
However, they tend to consume more fiber, polyunsaturated fatty acids, folates, vitamin C, vitamin E, and magnesium.

Meanwhile, meat-eaters are more likely to have insufficient intakes of fiber, polyunsaturated fats, folates, vitamins D and E, calcium, and magnesium.

In short: all diets carry potential nutritional risks.

What About Global Micronutrient Deficiencies?

Worldwide, billions of people suffer from inadequate intake of essential micronutrients, particularly calcium, iron, and vitamins C and E, according to a study from Harvard T.H. Chan School of Public Health and other institutions.

Using global dietary data from 185 countries, the researchers found that deficiencies were widespread:

• 68% of people had inadequate iodine intake.
• 67% lacked sufficient vitamin E.
• 66% lacked sufficient calcium.
• 65% lacked sufficient iron.

More than half also lacked vitamins B2, B6, C, and folate. Only vitamin B3 and B1 levels were closer to adequate.

How to Prevent Deficiencies Through Diet?

Some countries, like the U.S., fortify basic foods with synthetic vitamins. Supplements can also help.
But these strategies don’t fully replicate the complex benefits of minimally processed, naturally nutrient-rich foods.

Critical nutrients to monitor include iron, zinc, folates, vitamin A, calcium, and vitamin B12 — deficiencies can cause serious and lasting health problems.

Even in wealthy countries, iron deficiency is common, especially among women.

Thus, improving the overall quality, quantity, and variety of unprocessed foods in our diet remains key. Whole foods contain over 70,000 natural compounds that work together to boost nutrient absorption, improve immunity, enhance satiety, and protect against disease.

Should We Really Eat “Varied” Diets?

The virtues of a “monotonous” diet:
In developed countries, variety isn’t always synonymous with better nutrition. A monotonous but well-designed diet — for example, based on cabbage, lentils, potatoes, whole-grain bread, vegetable oils, and modest amounts of animal products like liver and sardines — can often provide more nutrients than a varied but poorly balanced diet.

As Nicole Darmon points out, food variety can be a nutritional trap: it all depends on what kinds of foods you’re varying. For example, variety within processed categories like cheeses or deli meats doesn’t necessarily improve nutrition — whereas variety among fruits and vegetables does.