For the past 20 years, Serge Rezzi has been putting foods under the microscope to see how they impact our health. He explains why we need a range of micronutrients in our diet – and why our wider approach to nutrition needs a radical rethink.

Between the 16th and 19th centuries, scurvy killed more than two million sailors. Navy surgeon Usher Parsons described the symptoms of this disease, which struck down whole ship crews. First, it caused ‘ulcers at the nose and mouth’, later ‘all the evacuations from the body become intolerably fetid’, and finally, ‘death closes the scene’. And all because the sailors were deficient in vitamin C – they couldn’t access fresh fruit and vegetables during long voyages.

Since then, we’ve learnt much more about micronutrients. They are vitamins and trace elements that are vital for our bodies to function well. As well as vitamin C, they include a host of other vitamins – from B group vitamins to vitamins A, D, K and E – and mineral elements that are just as vital for human biology, like iron, zinc, magnesium, manganese and copper. Unlike macronutrients – proteins, fats and carbohydrates – micronutrients don’t serve as direct energy sources, and we need them only in relatively small quantities. But they’re no less essential to keep our biological processes running smoothly.

A single vitamin wears many hats

We tend to associate vitamins with a specific function: vitamin E is an important antioxidant, vitamin K is key for blood coagulation and vitamin A is important for our vision, immune system and cell division.

But this belies a more complex reality. Vitamins are pleiotropic agents, meaning they work at many levels of our biochemistry and biology. We cannot reduce a vitamin to having a single health benefit. Micronutrients are part of complex networks and biochemical reactions, so it makes sense that when they are missing, our bodies stop functioning as they should. Over long periods, deficiencies may contribute to the development of complex diseases or their comorbidities. Modern diseases are multifactorial – meaning they have several causes – so we can’t pinpoint a single vitamin deficiency as the culprit but, in the long run, it’s clear that micronutrient gaps can have a huge impact on our health.

In light of this, the solution seems simple. We need to eat a balanced and varied diet to get enough of each micronutrient. Except, nutrition is never simple. Our lifestyles mean we often choose convenient food, rather than what is good for us – and for our cells. Many people assume that as long as they feel full and satisfied, their bodies are getting what they need. This is absolutely not the case.

Take obesity: it’s a misconception that obese people will not have any deficiencies because they’re ingesting enough calories. In truth, they are often deficient in micronutrients –commonly vitamin D or zinc, for instance – as obesity affects the way people absorb and metabolise micronutrients.

The dangers of hidden hunger

This is an example of what we call ‘hidden hunger’, or malnutrition caused by micronutrient deficiencies that are not always apparent. We call it ‘hidden’ because it doesn’t come hand in hand with the immediate symptoms – like weight loss – that we usually associate with malnutrition. The upshot? Suboptimal levels of micronutrients start causing problems a long time before we see any symptoms.

Hidden hunger affects all age groups in both developing and developed countries, but it’s particularly prevalent in certain groups, like older people. As we age, our skin gradually loses the ability to synthesise vitamin D, which makes us more prone to vitamin D deficiency. Additionally, older people commonly suffer from loss of appetite or dysphagia (difficulty swallowing), which can lead to a lack of nutrient intake. These factors can compound and spiral into poor health: deficiencies weaken the immune system, which in turn makes people more prone to diseases, ultimately reducing their independence.

Nutrient deficiencies cause a host of health problems across other age groups, too. One example is folate deficiency: if a mother doesn’t eat enough folate before and during early pregnancy, it can increase the risk of neural tube defects in her baby. One such defect is spina bifida – when the baby’s spinal cord does not grow properly – which has disastrous consequences.

One of the best ways of prolonging good health and eliminating hidden hunger is through preventative measures, like ensuring good nutrition at all stages of life. This means there needs to be a radical shift from cure to prevention, as health systems in Europe are still very much focused on the former. At the SNHf, we’re gathering data about micronutrient deficiencies in Europe for a groundbreaking study, so that decision-makers can implement effective prevention policies based on reliable micronutrient deficiency data (see box below for more information).

Less processing, more health benefits

Public health institutions and the food industry need to take more responsibility for people eating well. Yes, people should be free to choose what they eat and, to a degree, it’s up to them to make healthy choices. But it’s also a public health responsibility to ensure foods are safe and nutritious. All too often, food companies produce ultra-processed foods that lack nutritional value and contribute to unbalanced nutritional habits.

Take so-called ‘alternative’ proteins as an example. We start with an unprocessed food source like soy or pea. We then break down every single component of it through various processes, which gives us a series of different ingredients, such as protein isolates. Next, the ingredients are reassembled and processed to achieve the desired taste and texture. As this process often leads to nutrient loss, the final touch may consist of adding micronutrients that have been lost along the way.

I’m not waging a war on food processing here. It’s essential to make sure food is safe. But the current industrial approach of cracking, reassembling and fortifying ingredients needs to be revisited. We urgently need to shift how we produce food towards less invasive processing and more sustainable use of our limited nutrient reserves, for both health and environmental reasons. This will become all the more important as the global population continues to grow.

Innovation, not renovation

For me, this is the core of the issue. Although some much-needed sustainability measures have been put in place, they remain somewhat lacklustre – and not nearly far-ranging enough to produce a real, global shift. Most companies right now simply copy their competitors’ products or food technologies, perpetuating the same approaches to sourcing ingredients and producing foods. Rather than innovating, they make tweaks to existing products.

Granted, innovative ideas can often be hard to turn into reality, but this means many companies settle for incremental innovation at best. Although this strategy may bring in revenue in the short term, it is short-sighted when we look at the bigger picture. I believe there’s a huge gap in the market for companies to reinvent the foods of tomorrow with sustainability and nutrition in mind.

The SNHf has recently introduced the concept of ‘nutrient efficiency’,(10.3389/fnut.2023.1248895) as a tool to produce sustainable food while taking into account environmental and nutritional goals. Our research shows that our definition of ‘sustainability’ needs to include not only environmental impact (e.g. carbon footprint), but also (on a molecular level) how dietary nutrients can effectively be absorbed and used by the body with minimal nutrient waste. To turn this concept into reality, we need to step away from what food companies are doing and start afresh. For example, we need to ask: what is the minimum process needed to make a safe food while preserving maximum nutrition? And how do we minimise loss of nutrients and environmental impact?

We’ll also need to move away from focusing only on the taste and texture of food. We seem to have forgotten that the reason we need food in the first place is to nourish our bodies. Aswe move forward, there will be gaps in the market for companies to come up with new, bold and creative solutions to producing food that is both sustainable and nourishing.