Anti-nutrients: allies or enemies?

Lectins have been reported to have potential negative effects on digestive health. Indeed, because they are resistant to the activity of digestive enzymes, lectins can remain intact in the digestive system (1). Studies have reported that exposure to large quantities of lectins can lead to leaky gut syndrome (1). It is characterized by increased intestinal permeability. (1)(2) The intestinal wall becomes more porous, allowing substances such as toxins and bacteria to leak into the bloodstream (1). This leakage triggers an immune response and can lead to inflammation throughout the body. (1) On the other hand, it is important to note that these disturbances were observed in the animal studies (2). Few studies have been carried out in humans on lectin consumption and digestive health (3).

Wheat, nuts, cereals, quinoa, beans, legumes, peas, carrots, tomatoes, peppers, eggplant, paprika, potatoes (1)(2)(3)

Studies report potentially negative impacts on intestinal health when lectins are consumed. These mechanisms were present in animal studies and these disturbances have not been observed in humans. Current science does not justify withdrawing or limiting the consumption of these foods. and, on the contrary, promotes nutrients such as prebiotics for digestive health!

Tea, coffee, cocoa, grapes, apples, apricots, berries, stone fruits, nuts, wine (1)(3)

Tannins appear to interfere with the absorption of certain nutrients. Indeed, they can act as chelators, slowing the absorption of minerals such as iron, copper and zinc (3). Thus, tannins seem to be associated with reduced iron absorption and reserves in the body (1)(3)(4).

On the other hand, the impact of tannins on iron is not well known. no consensus in studies. In fact, epidemiological studies (of populations) only report no correlation (link) between dietary tannin intake and iron-deficiency anemia (3).

Nevertheless, to reduce the potential impact of tannins on iron absorption, it is recommended to separate tea and coffee from meals (3). Also, pairing the consumption of tannin-rich foods with a dietary source of vitamin C, The use of a wide range of products, such as vegetables and fruit (e.g. broccoli, peppers, strawberries, apples, citrus fruits), reduces its potential impact (3).

Research reports the benefits of tannins through their high content of polyphenols (3). Having roles antioxidants, Polyphenols are associated with a reduced risk of type 2 diabetes and cardiovascular disease (3). What's more, polyphenols are prebiotics for intestinal bacteria (3).

Tannins appear to possibly impair iron absorption from the diet (1, 3). Combine them with a source of vitamin C (e.g. vegetables, fruit) is one way of reducing their impact (3). In addition, distancing coffee and tea from meals is a preventive behavior. Pay more attention to tannins if you have higher needs (eg. woman, pregnancy) or that iron sources are more limited in your diet (ex. vegetarianism, veganism). On the other hand, no study has shown the need to limit tannin intake. From benefits are documented for their polyphenol content, an antioxidant that promotes overall health (1)(3)!

Cruciferous vegetables (cabbage, broccoli, cauliflower, kale, Chinese cabbage, turnip), sweet potato, soybean, millet, cassava (1)(2)(3)

Goitrogens are reported to inhibit (impair) the absorption of’iodine and synthesis of thyroid hormones (1)(2)(3). This association is explained by the fact that goitrogens can reduce iodine release from the thyroid gland by acting as a competitive inhibitor (2). Thus, goitrogens can interfere with thyroid function and increase the risk of certain diseases. thyroid diseases such as hypothyroidism and goiter (1)(2)(3).

On the other hand, these associations with disease risk are controversial in the literature, with results differing between studies (2). The adverse effects of goitrogens are present when a low iodine diet (2)(3). Thus, for people with thyroid disease (e.g. hypothyroidism, hyperthyroidism) or who are at greater risk of these diseases, it is important to focus on adequate iodine intake in the diet to limit the potentially harmful effects of goitrogens.

Examples of iodine-rich foods Fish, seafood, iodized salt, dairy products, eggs, seaweed.

On the other hand, in people without thyroid disease, or who are not at risk of thyroid disease, goitrogens are not associated with a risk of serious health damage when consuming a balanced diet (3).

The consumption of goitrogens seems to be associated with some benefits on health, including reducing thyroid cancer and improving metabolic and neurodegenerative diseases (2, 3). These benefits appear to be attributed to their roles anti-inflammatories (2).

Foods rich in goitrogens seem to interfere with thyroid function. If you have a thyroid disease (e.g. hypothyroidism, hyperthyroidism), it is important to have adequate iodine intake in your diet to limit their potential impact! For other people, no study has shown the need to limit the intake of goitrogens, but on the contrary!

Spinach, kale, broccoli, rhubarb, beet greens, amaranth, taro, Swiss chard, sweet potatoes, soybeans, walnuts, sorrel, legumes (1)(2)(3)

Oxalates are associated with reduced absorption several minerals, including zinc, iron, calcium and magnesium (1, 3, 4). In addition, many report that high consumption of oxalate-rich foods can contribute to the formation of kidney stones, or the kidney stones (1)(2)(3)(4).

One way to reduce the impact of oxalates is to consume them with calcium-rich foods (1)(2). In fact, the risk of kidney stone formation is higher in people with lower dietary calcium intakes (1)(2)(3).

Examples of calcium-rich foods Dairy products (milk, yoghurt, cheese), fortified plant-based beverages, green vegetables, fish, legumes, tofu.

Recent scientific data also mention that the impact of oxalates on kidney stones is less overall than has been the case in recent years, and the consumption of animal proteins has a greater impact than plant proteins (3)!

Given the potential links to kidney stone formation, you may want to pay attention to their intake if you're at risk for this condition. Combining the consumption of oxalate-rich foods with a healthy diet is a good way to reduce the risk of kidney stones. source of calcium helps limit this risk. In addition to this context, consumption of oxalates is not limited by a balanced diet.

Pulses, cereals, oats, beans, amaranth, nuts, seeds (1)(2)(3)(4)

There is some evidence that phytates may interfere with the absorption of several minerals including zinc, iron, calcium and magnesium (1, 2, 3, 4). Like tannins, phytates are chelators of these nutrients, limiting their absorption (2, 3).  

Combine the consumption of foods rich in fibers and in vitamin C to those rich in phytates could minimize their potential negative impact (2, 3). For example, pairing the consumption of legumes with vegetables or fruit, The inclusion of high-fiber, vitamin C-rich foods in the same meal helps limit the impact on nutrient absorption.

Several studies report that phytates have positive effects, as they are rich in antioxidants (2) (3). Their consumption is associated with a reduced risk of certain chronic diseases such as diabetes and cardiovascular disease (1) (2).

The benefits of phytate-containing foods for human health outweigh their potential effects in reducing mineral absorption (3).