The addition of turmeric to popular street-vended drinks can help prevent malnutrition in developing countries. Folake Idowu-Adebayo found that turmeric-fortified soya milk, cow milk and Hibiscus drink increased in micronutrients. However, the effects depended on the type of drink, emphasizing the role of the food matrix. She defended her PhD thesis in September.
The supposed health benefits of turmeric are legion, ranging from antioxidant and anticancer to antivenom. Folake Idowu-Adebayo (Food Quality and Design) intended to use turmeric to reduce malnutrition in her home country, Nigeria. ‘In literature, curcumin is often indicated as the major compound working the wonders of turmeric,’ says Idowu-Adebayo. ‘But besides curcumin, there are other bioactive compounds in turmeric, such as curcuminoids and essential oils.’
In addition, the technology to extract curcumin may be too expensive for street food vendors and small-scale food processors in Nigeria. Hence, Idowu-Adebayo decided to study the effect of adding whole turmeric root to drinks. She combined turmeric with two popular drinks sold by Nigerian street vendors: zobo and soya milk. Zobo is made by boiling the scarlet calyces of Hibiscus sabdariffa in water.
The food technologist analysed nutritional compounds of the turmeric-fortified zobo with 2 or 6 percent turmeric, boiled or unboiled. ‘There was a sharp increase in vitamin C in the 2 percent dosage, which is surprising because turmeric does not contain this vitamin.’ Boiling can release precursors of vitamin C from turmeric, which may degrade to vitamin C in reaction with other compounds in zobo. This could be an effect of the food matrix: the combination of ingredients in a food product influences the health benefits of the individual ingredients. The lower vitamin C content in 6 percent boiled turmeric in zobo could be due to precipitation of the vitamin precursors at higher concentrations.
Turmeric golden milk has gained popularity globally. Idowu-Adebayo studied plant-based milk from soya beans as a means to release the bound antioxidants in turmeric, and compared it to cow milk as a carrier. ‘Soya milk proved a better carrier of turmeric antioxidants than cow milk,’ she concludes. Again, this shows the effect of the food matrix and how foods act in synergy. For instance, essential oils in turmeric (turmerones) could react with vitamin E (tocopherol) from soya milk and slow down harmful oxidation.
Her work shows that the food product to which turmeric is added influences its health-supporting effects. Idowu-Adebayo therefore pleads for studying the benefits of turmeric not by looking at curcumin in isolation but rather by looking at the turmeric rhizome as a whole and in relation to the other ingredients in the food product. ‘If researchers consider the food matrix effect in their experiments, they may find the scientific evidence for the purported health benefits connected to turmeric since ancient times.’