A Mexican scientist says eating too many 'super fruits' can have negative impacts on health, website Eluniversal.com.mx reported.

Mexican National Autonomous University's (UNAM) scientist Agustín López Munguía, told the website too many antioxidants could affect regulatory functions or neutralize the body's defense mechanisms that depend on natural oxidants.

The scientist said the consumption of antioxidant-rich fruit and vegetables was appropriate for healthy servings and a balanced diet, but too much could be damaging, the story reported.

"Another problem is the inclusion of exotic varieties like the kiwifruit, native to southern China and introduced in New Zealand at the start of last century, as although it has many beneficial properties for health (nutraceuticals), today it is known as one that generates more allergic reactions in people who are not used to consuming it," another UNAM academic secretary told the website.

The story pointed out grapes were rich in phytochemicals, but in large amounts the sugar content could mean a significant amount of calories, which would be counterproductive for people who were overweight or wanted to substitute away from soft drinks.

The benefits and limits of nutraceutical foods

Lopez Munguia said nutraceutical fruits and vegetables were those that had curative or preventative properties against disease, which means antioxidants are included but the term itself is much broader.

Other nutraceutical foods can include those associated with anti-inflammatory agents or inhibitors of cancer cell development, while antioxidants themselves are associated with low cholesterol levels. If any fruit has high levels of any of these properties it is classed as 'super'.

The story highlighted super fruits such as noni fruits, rambutan, açai, mangosteens, pomegranates, kiwifruit and berries, but blueberries can also interfere with the elimination of urinary tract infections.

López Munguía said many experiments conducted to illustrate these properties in laboratories involved high concentrations that were well above those found in fruit.

"To match an experiment done with animals that are prone to diabetes or neurodegenerative diseases would require an enormous intake of nutraceutical fruit. So, these virtues are manipulated to sell," he was quoted as saying.

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