Origin of the «superfood»
The concept of "superfood" is popular when it comes to food and health. Headlines in the media are littered with reports of ultra-healthy foods, such as blueberries, beets, cocoa, and salmon. These reports want to convey the most recent scientific findings to the reader or viewer, and ensure that if we eat these foods, our bodies will get the necessary boost to prevent diseases and aging. Another question is whether there is any truth to these reports.
Probably, the current attention paid to so-called superfoods has been given by a growing interest of the general public in food and health, especially in the developed world1. Although it has been determined that the first time the term itself was used was at the beginning of the 20th century, its popularization in everyday language is a very recent fact2. A simple search for the word "superfood" on the Internet brings up nearly 10 million results, mostly from health and nutrition blogs, online newspapers and magazines, and nutritional supplement vendors.
However, despite its omnipresence in the media, there is no official or legal definition of "superfood". For example, The Oxford English Dictionary describes the term "superfood" as "a nutrient-rich food considered to be especially beneficial for health and well-being," while the Merriam-Webster dictionary omits any reference to superfood. health and the term is defined as "food rich in nutrients, full of vitamins, minerals, fiber, antioxidants and / or phytonutrients" 3,4. In general, the term superfoods refers to foods, especially fruits and vegetables, whose nutrient content gives them a health benefit greater than that of other foods.
What evidence is there?
In order to distinguish between the truth and the hype, it is important to carefully examine the scientific evidence behind the claims of the media about superfoods. For example, blueberries are one of the most popular and well-known superfoods, and have been the subject of frequent studies by scientists who were curious about their health properties. High concentrations of a group of plant antioxidant compounds present in blueberries, especially the so-called anthocyanins, have been reported to inhibit the growth of human colon cancer cells, by destroying them5. Furthermore, blueberries are rich in other antioxidants, which have been found in rats to prevent and reverse age-related memory loss6.
Antioxidants are molecules that protect the cells of the body against free radicals, which are harmful. These free radicals come from sources such as alcohol and tobacco smoke, and are also generated naturally in the body during metabolism. If there are too many free radicals in the body, it can be subjected to oxidative wear and tear, which, in turn, causes cellular damage that can lead to age-related diseases such as cancer, diabetes and heart disease7.
Superfood rank has also been "awarded" to other fruits, such as acai and pomegranate. Acai-based fruit pulp has been shown to have powerful antioxidant properties, although it has yet to be confirmed that it may have health benefits in humans8,9. Studies carried out with pomegranate juice have shown that it can lower blood pressure in the short term, as well as reduce oxidative stress (wear), in healthy people10,11. Both elements (blood pressure and oxidative stress) are important risk factors for the development of heart disease.
As in the case of pomegranate juice, it has been suggested that beets would be a heart-healthy superfood. Its high levels of nitrate have been claimed to be converted into nitric oxide by the body, and nitric oxide is known to reduce blood pressure and the tendency for blood to clot (among other functions it performs) in human beings. humans 12. Similarly, cocoa has been claimed to dramatically reduce the risk of heart disease by lowering blood pressure and increasing the elasticity of blood vessels. It is believed that these effects are due to the high content that cocoa has of compounds called flavonoids13,14. Finally, salmon has often been included in the superfood lists based on mounting evidence pointing to the possibility that omega-3 fatty acids in salmon and other fatty fish prevent heart problems in people with high risk of suffering from cardiovascular diseases, as well as alleviating joint pain suffered by patients suffering from rheumatoid arthritis15–17.
A more thorough examination
This is just an illustrative sample of the many studies that have attempted to explore the health benefits of various foods. At first glance, they seem to support the existence of certain superfoods: indeed, the nutrients contained in these foods have been shown to have various beneficial properties for health. However, if a more objective perspective is adopted, the truth is that there are difficulties when applying the results of these studies to real diets. This is because the conditions in which food is studied in laboratories often differ greatly from the way in which those foods are normally consumed by people in their daily lives.
One of the main characteristics of the research carried out in this field is that it tends to use very high levels of nutrients, which are usually not achievable, from a realistic point of view, within a normal diet. Furthermore, the physiological effects of many of these superfoods are only short-term12,13. This means that people would have to consume them frequently to derive any health benefits from them and, in fact, such frequent consumption could be counterproductive, especially in the case of certain foods: for example, frequent consumption of cocoa in the form of Chocolate would increase the intakes of the healthy flavonoids present in cocoa, but also those of other nutrients that it is recommended to consume less or not consume at all.
In any case, probably one aspect that should be taken into account when examining this type of study is that in many of them the tendency is to use animal models such as, for example, rats, or to carry out in vitro experiments using isolated batches of human cells. Therefore, these types of studies are useful for scientists to get an idea of what the health properties and physiological mechanisms of the compounds present in certain foods could be, but they do not offer any guarantee that these compounds will have the same effects on people when they are consumed in the diet. Investigating effects in humans is a complex task: diets, genes and lifestyles vary from one person to another, making it difficult to study the effect of nutrients on health. In other words, to explore the effects in humans, a different approach is needed from the one used in animal and cell culture studies; Ideally, such an approach should include intervention studies (in which researchers manipulate the diet to determine the effect of a food or nutrient) and observational studies (in which researchers observe the effects of natural differences in the people's diets).
A final point to keep in mind when examining studies on the "health properties" of foods is the fact that many researchers study foods in isolation. Since people normally consume combinations of foods, selecting and isolating a food for study does not reflect the true consumption of food by humans. What's more, there is evidence that, in some cases, the simultaneous consumption of different foods can increase the body's ability to absorb nutrients. For example, the beta-carotene in carrots and spinach is more easily and quickly absorbed when ingested with a fat source, such as a salad dressing18. This type of evidence points to the benefits of a diet based on a wide variety of nutritious foods, versus the alleged benefits of a diet based solely on one superfood or a small set of superfoods.
The idea that there are foods that have extraordinary health benefits is very attractive, and it has undoubtedly increased the interest of the general public in the so-called superfoods. And in fact, from a scientific point of view in this field, it has been shown that certain compounds or components present in food and beverages can be especially suitable for people. This is also reflected in the existence of approved health claims, for which the European Food Safety Authority (EFSA) has considered that there is a sufficiently convincing body of scientific evidence19. However, it is not realistic to expect that a small set of "superfoods" will significantly increase our well-being. When looking at the claimed evidence for superfoods, it is necessary to be realistic as to whether there are truly health benefits to be gained from our actual diets.
Furthermore, the very act of calling certain foods "superfoods" in the media could give rise to the impression that other foods in our diets are not as healthy, when the truth is that other foods tend to provide us with Nutrients as valuable as those found in "superfoods." For example, carrots, apples, and onions are rich in healthy nutrients like beta-carotene, dietary fiber, and the flavonoid quercetin20. Whole grain varieties of cereal-based starchy foods, such as bread, rice, and pasta, are also very high in dietary fiber. In adults, dietary fiber intake should be at least 25 grams per day21. The foods just mentioned often have the added benefit of being cheap and widely available, which means that we can easily consume them in large enough amounts on a regular basis to make the most of the nutrients they contain. Likewise, most Europeans do not eat enough fruit and vegetables to meet dietary recommendations, so increasing our daily intake of a wide variety of fruits and vegetables will greatly help us increase overall. our well-being22.
To ensure a balanced intake of nutrients for good health, we must increase the range of nutritious foods that we include in our diets, rather than focusing exclusively on a small set of foods that have been claimed to be "super ». And something very important: our diets must include a greater quantity and variety of fruits and vegetables. Many European countries offer food-based dietary guidelines designed to help people achieve that goal23.
1. European Commission (2010). Functional foods. DG Research. Brussels, Belgium.
2. The Gleaner (1915). Kingston, Jamaica, June 24, 2/18.
3. Oxford English Dictionary, online edition, "superfood" entry, www.oxforddictionaries.com /. Retrieved April 24, 2012.
4. Merriam-Webster Dictionary, online edition, the entry "superfood", www.merriam-webster.com/. Retrieved April 24, 2012.
5. Yi W et al. (2005). Phenolic compounds from blueberries can inhibit colon cancer cell proliferation and induce apoptosis. Agric Food Chem 53 (18): 7320–9.
6. Malin DH et al. (2011). Short-term blueberry-enriched diet prevents and reverses object recognition memory loss in aging rats. Nutrition 27 (3): 338–42.
7. Dröge W. (2002). Free radicals in the physiological control of cell function. Physiol Rev 82 (1): 47–95.
8. Lichtenthäler R et al. Total oxidant scavenging capacities of Euterpe oleracea Mart. (Açaí) fruits. Int J Food Sci Nutr 56 (1): 53–64.
9. Hassimotto NMA et al. Antioxidant activity of dietary fruits, vegetables, and commercial frozen fruit pulps. J Agric Food Chem 53: 2928–35.
10. Lynn A et al. (2012). Effects of pomegranate juice supplementation on pulse wave velocity and blood pressure in healthy young and middle-aged men and women. Plant Foods Hum Nutr 67 (3): 309–14.
11. Aviram M et al. (2000). Pomegranate juice consumption reduces oxidative stress, atherogenic modifications to LDL, and platelet aggregation: studies in humans and in atherosclerotic apolipoprotein E – deficient mice. Am J Clin Nutr 71 (5): 1062–76.
12. Webb AJ et al. (2008). Acute blood pressure lowering, vasoprotective, and antiplatelet properties of dietary nitrate via bioconversion to nitrite. Hypertension 51: 784–90.
13. Kris-Etherton PM & Keen CL. Evidence that the antioxidant flavonoids in tea and cocoa are beneficial for cardiovascular health. Curr Opin Lipidol 13: 41–9.
14. Hooper L et al. Flavonoids, flavonoid-rich foods, and cardiovascular risk: a meta-analysis of randomized controlled trials. Am J Clin Nutr 88 (1): 38–50.
15. Kris-Etherton PM et al. (2003). Fish consumption, fish oil, omega-3 fatty acids, and cardiovascular disease. Arterioscler Thromb Vasc Biol 23: e20 – e30.
16. Delgado-Lista J et al. Long chain omega-3 fatty acids and cardiovascular disease: a systematic review. Br J Nutr 107 (Suppl 2): S201–13.
17. Goldberg RJ & Katz J. (2007). A meta-analysis of the analgesic effects of omega-3 polyunsaturated fatty acid supplementation for inflammatory joint pain. Pain 129 (1–2): 210–23.
18. Brown MJ et al. (2004). Carotenoid bioavailability is higher from salads ingested with full-fat than with fat-reduced salad dressings as measured with electrochemical detection. Am J Clin Nutr 80: 396–403.
19. EU Register on nutrition and health claims: http: //ec.europa.eu/nuhclaims/
20. Crozier A et al. (1997). Quantitative analysis of the flavonoid content of commercial tomatoes, onions, lettuce, and celery. J Agric Food Chem 45 (3): 590–5.
21. EFSA panel on dietetic products, nutrition and allergies (2010). Scientific opinion on dietary reference values for carbohydrates and dietary fiber. EFSA Journal 8 (3): 1462. Available at: http: //www.efsa.europa.eu/en/efsajournal/pub/1462.htm
22. EUFIC reports (2012). Fruit and vegetable consumption in Europe - Do Europeans get enough? Http: //www.eufic.org/article/es/expid/Consumo-frutas-verdura-Europa/
23. EUFIC Reports (2009). Food-based dietary guidelines (FBDG) in Europe http://www.eufic.org/article/es/expid/dirementales-dieteticas-basadas-alimentos-Europa/