With the arrival of the cold, 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 that they consume some of the many 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 to the belief that a single superfood can provide superhealth, even if all else fails. This nutritional amulet can also take the form of a detox diet (even if those who consume them are not actually intoxicated). The marketing of detox diets warns, as reported by Harvard University, that we are surrounded by harmful substances. Among other harmful effects, these toxins, often unnamed, weaken the immune system. But drinking a green smoothie or undergoing a detoxification treatment neither prevents nor cures colds or the 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 Science and Technology of Food and Nutrition of the CSIC, you have to be careful with these products “because most of the time they are of no use”, she points out. “There are friends of mine who have a very unhealthy diet and who think that a detox product is enough for them,” he explains. But no. “Some of my acquaintances do what they want and are overweight, so their immune system is getting worse,” this pharmacist emphasizes. “The immune system is taken care of by eating well, doing physical activity and managing stress. All this may seem very silly, because it is the usual, but in the end it is the only thing that has been proven to work”, he recalls.
According to several videos circulating on TikTok about some of the methods that allegedly optimize the immune system, it can be aloe vera, vitamin C, betaglucan, colostrum, chicken egg yolk or maitake mushroom extracts. A situation to which other countries are not strangers, which is why the School of Public Health at Harvard University has recently spoken out on this issue.
“Consuming supplements to strengthen the immune system is a waste of time and money,” sums up Basulto. “In addition to not working, in Europe it is forbidden to attribute to a food product the supposed magical ability to improve defenses”, he adds.
According to this expert, although several nutrients participate in the immune system, this does not mean that an extra dose improves defenses. Accepting this is like considering the immune system a small, localized system, with the potential to be easily modified by taking a simple supplement. However, immunity does not seem to be amenable to partial and spot remedies. In other words: the immune system we have, by virtue of our genes, past infections or the composition of the microbiota, does not change substantially because an extra amount of some vitamins is ingested. What’s more, “it can become harmful”, warns Marcos, since the body does not absorb more in the intestinal area than it needs, therefore, it eliminates the rest. “That’s why it’s so important to undergo a blood test to determine if we lack any vitamins or minerals and, from there, have a professional prescribe a supplement that solves this deficit,” adds the former president of the Spanish Federation of Nutrition, Food and Dietetic Societies (Fesnad) between 2015 and 2020.
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 widely known: eat healthily throughout the day, do not smoke or drink alcohol, do regular physical activity to mobilize the cells involved in the immune response, keep at a healthy weight, get enough sleep, manage stress, and take steps to prevent infections such as washing your hands often.
Perhaps, the specialists point out, a day will come when we will know how to strengthen the immune function beyond the measures that are currently vox populi, but, for now, we must stick with the only one that has been shown to it works.
Today, Basulto indicates, the European Food Safety Authority (EFSA, by its acronym in English) has not approved any health declaration related to immunity to any food, dietary supplement or “medicinal plant”. Some nutrients and substances that have not passed the cut in the scientific literature are omega 3 fatty acids, probiotic bacteria, the bacteria responsible for the fermentation of milk, melon extract, garlic pearls, the germ of wheat, royal jelly, fermented milk products, lecithin, brewer’s yeast, lycopene from tomato juice, honey, bacteria present in many types of yogurt, propolis, and pomegranate or other fruit juice. “Strengthening immunity is what vaccines do”, explains Basulto.
In the last thirty years, dietary supplements have experienced a huge boom, after going from 4,000 products in existence in 1994 to more than 95,000 that are available in the United States market today. These capsules, effervescent tablets, sachets of powder, bottles of liquid, yogurts and infusions that populate the shelves of pharmacies and supermarkets almost always incorporate signs of the type “helps” or “reinforces” the immune system.
However, despite the fact that there are very few situations where they have been shown to be beneficial to health, thousands of people continue to rely on their effectiveness, to the point that when you type in the Google bar “supplements for to the immune system”, more than 14 million results are obtained.
But none of these remedies have been able to confirm the countless health benefits that their manufacturers boast. Moreover, when researchers have subjected them to rigorous tests, they have not ratified the benefits that were expected, they have even sometimes found risks.
The Anglo-Saxons designate supplements that boast of “reinforcing” or “favoring” the immune system with the term overpromises (‘promise in excess’). This is a fairly common tactic in the food industry that leads some companies to launch deceptive marketing campaigns that overestimate the characteristics of a product in order to capture the more customers the better.
However, there is no convincing evidence that a food or product is able to significantly improve immune function in healthy people. On this particular, the results of studies conducted on various supplements for warding off colds and other similar infections have been mixed at best. Even when taking the supplement was linked to a reduction in the severity or duration of a cold, it could not be proven 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”, remembers Basulto, “and not the foods that make it up separately”.
The EFSA recognizes, however, that some of the vitamins and minerals (such as copper, folates, iron, selenium, zinc, vitamins A, B6, B12, C and D) participate in the correct functioning of the defense mechanisms that protect against pathogenic agents. Even so, this does not mean that an extra contribution of these components improves immunity or that there are deficiencies of these nutrients in the population.
