New Zealand soil is known to be low in Selenium especially in the South Island. According to the Medsafe website updated in 2000, we are all ok and don’t need to supplement, especially if we eat adequate selenium containing foods and in particular if they are imported from elsewhere where the hope is that the selenium in the food will be higher than the local levels.
It is always best to get your nutritional requirements from diet as much as possible, so why not just have a couple of brazil nuts per day. However, if you are at particular risk of a health condition, it may be appropriate to include even more of the right foods in your diet and then supplement if necessary.
Apart from Brazil nuts (by far the most abundant source), other sources include wheat germ, whole grain bread, barley, eggs, mushrooms, legumes, liver, kidneys, rabbit, chicken, herring, shellfish, asparagus, cabbage, garlic, onions, radish, tomatoes, etc.
Selenium is a metallic antioxidant – its stops things going ‘rancid’ in your body or oxidizing. It does this because it is associated with the most important antioxidant of them all – Glutathione. This prevents free radical build up and consequent cancer and disease.
The cancers that can be associated with very low Selenium include:
Other major illnesses it is associated with include:
Depending on who you use as a reference, the daily requirements for selenium would be around 40mcg or so. If you are pregnant, it should be higher.
A very good source of selenium is Brazil nuts – one ounce or 28g contain 544mcg. If you are taking a supplement, you don’t need brazil nuts.
Some people may be advised to take larger doses by their health care providers. These people include those with prostate or bowel cancer.
Beware – “more is not better” – too much selenium can be harmful and cause a condition called Selenosis – garlic breath, brittle hair and nails and neurological disorders.
Is your Selenium adequate? PDF (287KB)
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