Have you noticed a recent decline in your sense of taste or smell? Perhaps this may not be immediately apparent; it may be your interest in food seems to have diminished. For mums you could be looking at those picky eaters; kids that turn their noses up most foods, not just their greens. Also consider the elderly, the tea and toast generation, who don’t seem to bother much with food. What could appear a lack of interest in food can be the result of diminished smell and taste, as they greatly influence our desire to eat.
When looking at what can be done to remedy this situation one nutrient that should be considered is zinc. Zinc is essential for 100’s of functions in the body and is needed for smell, taste and saliva production. So what is its involvement? Well, when looking at taste the gustatory or taste cells are located in the taste buds that are visible on the tongue. When we eat these taste receptors pass messages about the taste of the food to the brain. These go to the reward centre of the brain which allows us to feel pleasure from eating, motivating us to eat more or aversion if what we taste is not good. The messages from the taste buds also trigger a response in the digestive system for the processing of the ingested foods. Zinc is used in the taste buds and is important in their proliferation and zinc deficiency has shown a reduction in taste buds. (5)
Zinc is also used in the production of saliva, its secretion and the pH of saliva. As a component of saliva it acts as an anti-bacterial agent to protect oral health. Saliva is important for taste as it transports taste chemicals in the mouth. These taste chemicals are used by the taste cells in the taste buds to differentiate the 5 taste senses sweet, salty, bitter, sour and umami. Finally, with regards to smell the same zinc enzyme called carbonic anhydrase (CA) used in taste buds also helps the function of the olfactory or smell systems. (4)
Understanding the importance of zinc to taste and smell we can understand how it has been linked with eating and taste disorders. Taste disorders are on the increase and could in part be linked to potentially increasing zinc deficiency. So what can be causing zinc to be lost? Here are some common everyday factors that can lead to zinc deficiency.
Diet – Eating a diet of processed food can deplete zinc as its absorption is blocked by phosphoric acid. This is commonly found in sodas and flavoured waters drinks, cereal bars, processed dairy like cheese, processed meats, the list goes on. (1,2) Zinc is readily available in animal products, so those on vegan and vegetarian diets are more at risk. This is compounded by soils being low in zinc, so vegetables may contain less zinc than they did traditionally.
Medications – Many medications can lead to zinc deficiency such as protein pump inhibitors, antacids, anti-inflammatory medications, non-steroidal anti-inflammatories, oral contraceptives, ace inhibitors for blood pressure and diuretics to name a few. (3)
Digestive disorders – People with digestive disorders may also have poor zinc absorption as well as poor absorption of many other minerals.
If you are considering that you may have a poor sense of taste and smell other sign to look for are:
- White spots on the nails
- Mouth ulcers
- Kids may also suffer from regular diarrhoea
- Poor immunity
- Poor night vision
- Sugar cravings
- Poor growth in children
- Wounds that heal slowly or won’t heal.
By Jane Cronin
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Yagi T1, Asakawa A, Ueda H, Ikeda S, Miyawaki S, Inui A. The role of zinc in the treatment of taste disorders. PMID: 23305423 Accessed27-7-16