Skip to 0 minutes and 0 seconds[music] -Hello, and welcome back. In a previous lecture, we started discussing how dietary guidelines for micronutrients are drafted, focusing on the recommended or adequate in-takes. We will continue our discussion by talking about the risks of superfoods, from overdosing, to interaction with medicines and contaminations. Just as we have reference values that indicators the recommended daily value of a nutrient, in some cases, the guidelines indicators are tolerable upper intake level. Exceeding these limits can sometimes result in medical symptoms. It is the case, for instance, of vitamin A hypervitaminosis. Even if fruits and vegetables cannot cause this condition, some foods that are particularly rich in preformed vitamin A, could be toxic.

Skip to 1 minute and 18 secondsIt's the case, for instance, of the liver of certain animals, and of cod liver oil, but are there patterns of consumptions, especially of superfoods, that could be detrimental for our health, because of an excessively high amount of micronutrients? Let's take one of our examples from a previous lecture; Kale.

Skip to 1 minute and 46 secondsKale is very high in vitamin C and vitamin K, but neither of these vitamins poses a quantifiable risk of toxicity, even when consumed above the recommended threshold. To the point that there is no tolerable upper intake level for both of them. This does not mean that it is always safe for everybody. People taking blood thinners, such as warfarin, need to pay attention to their intake of green leaf vegetables, as they are rich in vitamin K. There are other examples. Omega-3s contained in many superfoods, from fish oil to walnuts, can interact with blood thinners, and with medications that lower blood sugar.

Skip to 2 minutes and 34 secondsThere is another kind of health risk that can be linked to superfoods, even if it is not specific to them. This hazard derives from the particular susceptibility of some foods to contamination, and to the lack of knowledge about the specific toxins or contaminants. One example is kombucha or double fermented tea, which is often described as a miracle superfood. Kombucha is prepared by fermenting a mixture of tea, sugar, and other ingredients with another culture of bacteria and yeast. Homemade kombucha carries obvious risks, when the mixture is fermented for too long. In unhygienic conditions, or when the environmental condition can favor harmful strains of bacteria, but the same risks are present, even when we buy this product from unscrupulous commercial producers.

Skip to 3 minutes and 38 secondsThere are a few reported cases where toxicity has been attributed to kombucha consumption, but the toxin or contaminant was not determined, making impossible both to draw a clear conclusion, and to take countermeasures.

Skip to 3 minutes and 57 secondsSince, as of 2018, fermented and home fermented products are being touted as superfoods, it is worth to keep the risks in mind. Other superfoods such as spirulina, and similar algae dietary supplements, also pose a risk of contamination by toxins such as microcystins. In this case, however, the problem has been clearly identified and respectable producers test their product to exclude the presence of these contaminants. In conclusion, there is little risk of overdosing on goji berries and other superfoods, but supplements and extracts are not safe just because they are described as natural or super. Especially if you are suffering from a chronic condition, be sure to check with your doctor whether what you are eating is safe for you.

Are superfoods always safe?

Are superfoods always safe?

In the first video of the last week, we discuss some reasons why this might not always be the case. Some superfoods, like kombucha, might be particularly susceptible to contaminations, and were linked to toxicity in a few cases. Others, like spirulina, were found to be contaminated with specific bacterial toxins, but most manufacturers now explicitly test their product to avoid this problem.

More in general, food can have interactions with medicines - for instance, because of their high vitamin K content. This is, for instance, the case of kale or other green leafed vegetables. Omega-3s, too, can interact with medicines.

However, generally speaking, superfoods are not dangerous, especially when included in a varied diet, as “overdosing” on them and ingesting an excessive amount of vitamins or other micronutrients is very unlikely.

Lastly: can superfoods be harmful due to their content of bioactive compounds? We will discuss this topic in the next steps of this week.

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This video is from the free online course:

Superfoods: Myths and Truths

EIT Food