We've all heard about them and how good they are for us and most of us take the odd multivitamin, but as our food system changes as well as the environment around us, there might be a need to get more than what was originally recommended.
Vitamins & Minerals
The world we live in today is extremely different from that of 10-20 years ago. With drastic improvements in technology, the use of nanoparticles has increased dramatically. Nanoparticles are ultrafine particles which are employed in a variety of everyday applications such as in sunscreens, clothing and even used in the food and pharmaceutical industries. Rough estimates suggest that the average person in a developed country consume billions to trillions of fine and ultrafine particles every day, most of them found in food additives such as stabilisers or anti caking agents (substances which prevent lumps being formed in the product).
While nanoparticles have been used innovatively to improve bioavailability of certain vitamins such as vitamin C by improving their stability, researchers have recently found that perhaps nanoparticles also inhibit the absorption of other minerals and vitamins2. Using in vitro (petri dish) and animal studies, scientists found that an acute ingestion of nanoparticles resulted in blunted iron absorption. The researchers highlighted concerns with other minerals such as zinc, calcium and copper which have very similar ways of transporting themselves into our circulation. Furthermore, fat soluble vitamins such as vitamin A, D, E & K are also potentially at risk due to disruptions in the absorption process.
While it is too early to offer any conclusive statements about the issue, it perhaps highlights that there are always drawbacks to the use of new technologies. It might also mean that the daily multivitamin and mineral supplement becomes more important in this day and age, even if our diets are seen as sufficient.
Getting More Out Of Your Food
Most of the vitamins and minerals come from the food thats we eat. Vegetables and fruits are considered higher in vitamins, while meat products are generally considered higher in minerals. When it comes to vegetables, if I asked whether you obtain more vitamins and antioxidants from consuming vegetables after cooking or in its raw form, what would you say? Assuming that the vegetables were fresh as can be, most people would consider that eating vegetables in its raw form is considered to provide the most nutrients. While some vegetables need to be cooked to be enjoyed, many people consider that the less cooking involved, the more nutrients that are saved and thus absorbed.
However, a current unpublished Australian study has observed an interesting phenomenon; that vitamin and phytochemical content is actually higher in certain vegetables that have been cooked compared to the raw product. A highly unusual phenomenon, the exact mechanism is still not yet fully understood, but is believed to be due to the presence and breakdown of tannins. Tannins are a chemical compound commonly found in teas and red wine, but also in a wide variety of fruits and vegetables including broccoli, spinach, peas, pumpkin and parsley. High intakes of tannins can inhibit protein, mineral and vitamin absorption. Heat can break down the tannins which then encourages absorption of vital nutrients contained in the vegetables.
Ironically, tannins are also part of a larger group of compounds known as polyphenols; which themselves have beneficial qualities including reducing the risk of heart disease, diabetes and even cancer. To get the most nutrition out of your vegetables, it’s important to cook many hard vegetables, but not to the extent that they turn into soup. Not only can it breakdown the tannins in the vegetables, heat can increase the amount of bioactive compounds, a protective mechanism of vegetables against heat damage3. It is also important to avoid excess consumption of high tannin drinks such as tea and red wine during meal times to get the most nutrients out of your meal.
2. Gretchen J. Mahler, Mandy B. Esch, Elad Tako, Teresa L. Southard, Shivaun D. Archer, Raymond P. Glahn, Michael L. Shuler. ‘Oral exposure to polystyrene nanoparticles affects iron absorption.’ Nature Nanotechnology, 2012; DOI: 10.1038/nnano.2012.3
3. Oboh G, Akindahunsi AA. ‘Change in the ascorbic acid, total phenol and antioxidant activity of sun-dried commonly consumed green leafy vegetables in Nigeria.’ Nutr Health. 2004;18(1):29-36.