What makes the mushroom different?
If you are like 4 out of 5 Australians you just love the taste of the mushroom, cooking it like it is a vegetable. Yet the mushroom is not a plant, evolving after fruits and vegetables first appeared on the planet. In fact, it is from completely different biological kingdom than plants. This explains why the mushroom is so nutritionally different to fruit and vegetables.
Probably the best example of how different the mushroom is to plants is its ability to generate vitamin D when exposed to UV light. Mushrooms have always been a source of vitamin D to our ancestors. Mushrooms, like humans, respond to sunlight by producing vitamin D. Some retailers in Australia offer vitamin D mushrooms that provide a day’s supply of D in just three button mushrooms. The mushrooms have been exposed briefly to UV light before packaging.
Alternatively, you can put mushrooms out in the sun for an hour or so (2 hours in winter) and they will naturally produce vitamin D. With one in three Australians having vitamin D deficiency, mushrooms could be a simple and enjoyable way to reduce the risk of getting too little of this vitamin.
The mushroom is also an excellent source of B vitamins such as biotin, pantothenic acid, riboflavin and niacin, with a serve of mushrooms providing about 25% of your daily needs of these vitamins. There is some vitamin B12 too, just a modest amount, but as you won’t find either B12 or D in plant foods does emphasise the difference between mushrooms and vegetables.
The mushroom and your weight
I can tell you a few facts like:
The mushroom is one of the lowest kilojoule foods around with only 103 kJ (24 Cals) in a normal serve of three button mushrooms or one flat mushroom
The mushroom has more protein than most vegetables and is very low in carbohydrate, similar to zucchini and tomatoes.
The mushroom is naturally cholesterol-free and virtually fat-free.
All true, but there is much more to the story. Mushrooms seem to help control your appetite. In a study where meat dishes were substituted with a serve of button mushrooms, the meal became more filling. Although the mushroom meal was 420 kJ (100 Calories) less than the meat meal, consumers actually ate 1565 fewer kilojoules (375 Calories) a day over four days. OK, that looks good over four days, but did the effect last any longer?
In April 2013, the same research group reported that people who ate a cup of mushrooms three times a week over a year lost 3kg and 6cm from around the waist when compared to those not eating mushrooms. This suggests that mushrooms have a powerful ability to make meals more filling to stop people over-eating over a long time.
Now, here is where it gets really interesting. The reason you love mushrooms is because they have that savoury flavour, known as ‘umami’. It is a Japanese term meaning ‘delicious’ or ‘flavoursome’ and comes primarily from the natural glutamates found in mushroom. These same glutamates have receptors in the mouth (taste buds) and throughout the digestive system. The theory is that these receptors send messages back to the appetite centre of the brain, so a mushroom meal makes you feel fuller for longer – a natural appetite suppressant.
What else should I know?
As many people now follow gluten-free diets it is reassuring for them to know that mushrooms are gluten-free. There is some wheat straw in the compost, but this doesn’t contain gluten. Some people are told to avoid mushrooms if they have gout. This is out-dated information. In fact, it seems that mushrooms actually help lower the risk of gout.
Mushrooms also have compounds that help control blood glucose levels and even lower blood cholesterol levels. It is the natural glucans in mushrooms that appear to have a cholesterol-lowering role, working in a similar fashion to medication given to people with high blood cholesterol. Of course, mushrooms don’t need a prescription from your doctor and everyone can benefit.
Do mushrooms have other healthy compounds?
Mushrooms are a rich source of antioxidants too. In an analysis of 30 common vegetables, mushrooms were placed in the top 5 highest antioxidant vegetables. Mushrooms are very high in the antioxidant ergothioneine, which has a role in the health of red and white blood cells. It is believed that ergothioneine protects the haemoglobin in red blood cells.
Researchers have found compounds in mushrooms that halt enzymes involved in the progression of breast and prostate cancer.
Researchers at the University of Western Australia found that, compared to women who didn’t eat mushrooms, those that ate an average of one button mushroom a day reduced their risk of breast cancer by 66%. Even those that ate only one mushroom a week had less risk of breast cancer (see chart above).
Nine other research studies have shown that eating mushrooms is associated with a lower risk of breast cancer (about a third to half lower risk). Although we have a good idea as to some of the compounds responsible for a lower risk, there is ongoing research on mushrooms and how they might lower both breast and prostate cancer risk.
How much mushrooms should I eat each day?
You only need to eat 100g of mushrooms each day to get all the nutrient and health benefits from a mushroom. That is only three button mushrooms or one flat mushroom. Easy. There is much more nutrition information, as well as a list of scientific references and recipes, at www.powerofmushrooms.com.au.
Accredited Practising Dietitian
21 November 2014