With the arrival of cold weather, it is common to resort to all kinds of remedies to strengthen the immune system. Despite the lack of empirical evidence, a high percentage of Spaniards admit to consuming the numerous products that fill the shelves of supermarkets and pharmacies. “They are used as if it were a talisman,” says dietician-nutritionist Julio Basulto.
The 'talisman effect' leads us to believe that a single superfood can provide 'super health' (even if everything else is not done well). This nutritional amulet can also take the form of a detox diet (although those who consume it are not really intoxicated). The marketing of detox diets warns, according to Harvard University, that we are surrounded by harmful substances and that, among other harmful effects, these toxins, often unnamed, cause the immune system to weaken.
However, drinking a green smoothie or undergoing a detox treatment, as rare as it may be, neither prevents nor cures colds or flu. And the same can be said of supplements that combine some vitamins with ingredients such as turmeric, milk thistle or echinacea.
For Ascensión Marcos, research professor at the Institute of Food and Nutrition Science and Technology of the CSIC, you have to be careful with these products, “because most of the time they are useless,” she highlights. “There are friends of mine who have a very unhealthy diet and who think that a detox product is enough for them,” she says. But not.
“Some of my acquaintances do whatever they want and are extremely overweight, so their immune system is getting worse (infections, allergies, etc.),” highlights this pharmacist. “The immune system takes care of itself by eating well, doing physical activity and managing stress. All of this may seem very silly, because it is the same as always, but in the end it is the only thing that has been proven to work,” she recalls.
According to several videos circulating on TikTok about some of the methods that supposedly optimize the immune system, they may be aloe vera, vitamin C, beta-glucan, colostrum, chicken egg yolk or extracts of the maitake mushroom or Grifola frondosa.
A situation to which other countries are no strangers, which is why the Harvard University School of Public Health has been forced to speak out recently on this matter.
“Consuming supplements to strengthen the immune system is wasting time and money,” summarizes dietitian-nutritionist Julio Basulto. “In addition to not working, in Europe it is prohibited to attribute to a food product the supposed magical ability to improve defenses,” he adds.
In the opinion of this expert, although various nutrients participate in the immune system, this does not mean that an extra dose of them improves defenses. Accepting something like this is like considering the immune system a small, localized system, with the potential to be easily modified by taking a simple supplement, for example.
However, the immune system does not seem to be susceptible to improvement with partial and specific remedies. In other words: the immune system we are born with is the one we have (by virtue of our genes, past infections or the composition of the microbiota) and it does not change substantially by ingesting an extra amount of some vitamins. What's more, "it can be harmful," warns Marcos, since the body does not absorb more than it needs at the intestinal level, so it eliminates the rest.
“That is why it is so important to undergo a blood test to determine that you lack some vitamin or mineral and, from there, have a professional prescribe a supplement that solves this deficiency,” adds Ascensión Marcos, who was president of the Spanish Federation of Nutrition, Food and Dietetics Societies (FESNAD) between 2015 and 2020.
To date, Basulto indicates, the European Food Safety Authority (EFSA) has not approved any health claim related to immunity on any food, dietary supplement or “medicinal plant.”
Some nutrients and substances that have not made the cut in the scientific literature are omega 3 fatty acids, probiotic bacteria, bacteria responsible for milk fermentation, melon extract, garlic pearls, wheat germ, royal jelly, fermented dairy products, lecithin, brewer's yeast, lycopene in tomato juice, honey, bacteria present in many types of yogurt, propolis and pomegranate juice (or other fruit juices). “Strengthening immunity is what vaccines do,” Basulto says.
In the last thirty years, dietary supplements have experienced a great boom, after going from 4,000 products in 1994 to more than 95,000 currently available on the US market. These capsules, effervescent tablets, powder sachets, liquid vials, yogurts and infusions that populate the shelves of pharmacies and supermarkets almost always incorporate labels such as “helps” or “strengthens” the immune system.
However, although there are very few situations in which it has been scientifically proven that they are beneficial for health, thousands of people continue to trust in their effectiveness, to the point that when "supplements for the immune system" are typed in the Google bar, and click and you get more than 14 million results.
But it must be insisted that none of these remedies have managed to confirm the innumerable health benefits that their manufacturers boasted. What's more, when researchers have subjected them to rigorous tests, they have not endorsed the benefits they expected, and sometimes they have even found risks.
The Anglo-Saxons designate supplements that claim to “strengthen” or “favor” the immune system the term “overpromises.” This is a fairly common tactic in food that leads some companies to launch deceptive marketing campaigns that overvalue the characteristics of a product to attract the largest possible number of customers.
However, there is no convincing evidence that any food or product is capable of significantly improving immune function in healthy people. In this regard, the results of studies carried out on various supplements to ward off colds and other similar infections have been, at best, uneven.
Even when taking the supplement was associated with a reduction in the severity or duration of a cold, it has not been possible to prove that the supplement in question boosted the immune system. The same goes for foods: none have been proven to improve immune function on their own. “The most important thing is the overall quality of the diet,” recalls Basulto, “and not the foods that make it up separately.”
The EFSA recognizes, however, that some vitamins and minerals (such as copper, folates, iron, selenium, zinc, vitamins A, B6, B12, C and D) participate in the correct functioning of the immune mechanisms. defense that protects from pathogens. However, this does not mean that an extra supply of them improves immunity, nor that there are deficiencies of these nutrients in the population.
In reality, strengthening the body's defenses is not a secret within the reach of a few, nor is it related to a magical product. Seen this way, the best way for the immune system to perform is well known: eat healthy throughout the day, do not smoke or drink alcoholic beverages, practice regular physical activity to mobilize the flood of cells involved in the immune response, stay in a healthy state. healthy weight, getting enough sleep, managing stress, and taking steps to prevent infections such as frequent hand washing.
Perhaps, specialists point out, there will come a day when we know how to strengthen immune function beyond the measures that are currently popular but, for now, we must stick with the only thing that has been proven to work.
