In Europe, the reishi mushroom is catalogued as “food” by the European commission (European commission’s Novel Food catalog). Nevertheless, as any other food, reishi is not free from side effects. It is important to bear in mind that food has also counter-indications, therefore herein are going to be exposed:
Let us begin with reishi’s toxicity: the conducted toxicity studies, in which variable doses of Ganoderma lucidum were given to rats, rabbits and dogs have not shown any signs of alteration to the main organs. Long term toxicity studies in rats have shown that doses up to 1,87 grams / 0,059 oz per day during a 26 week period, have not shown any kind of undesirable effects. Such consumption is equivalent to a daily dose of 112.2 grams / 39.57 oz of a 60kg / 132.2 pounds person. It is like having 4-month doses of reishi in just a day!
Due to the high level of activity that reishi has on the immune system, it should not be taken by patients subject to immunosuppressive therapies, like the ones carried out when patients have had, or are about to have an organ transplant, and are taking any kind of medication that suppress the immune system.
People taking immunosuppressive medicaments for any autoimmune disease should ask their doctor whether its consumption is recommendable. The little amount of research available about reishi and its application in patients with an autoimmune disease can be consulted through this link provided:
As reishi has slight anticoagulant properties, it is important to keep in mind that such properties might enhance the effect of anticoagulants such as Sintrom ( warfarin), Aspirin (acetylsalicylic acid), etc.
ATTENTION: should you be consuming reishi spores, mycelium or extracts, bear in mind that there are no studies conducted which assess the influence of them on blood coagulation. Through this link, you can see the differences between pure reishi mushroom and reishi’s spores, mycelium and extracts.
Reishi’s extracts will have different levels of toxicity, counter-indications and side effects, due to the fact that such extracts have just a few chemical elements of the mushroom.
Diabetes: Reishi mushrooms have the capacity to regulate blood sugar levels. Due to this, it is a highly recommended product to patients with diabetes type 2, 3 and 4 (reishi & diabetes, published investigations). People suffering from diabetes have to check their blood glucose levels more frequently owing to the fact that sugar levels might get low. It is highly recommendable to consume pure reishi mushroom only, so that patients can gradually increase the doses of the product, and minimize the possibilities of having a sudden drop of sugar levels.
Allergies: Until now, no hyper sensibility effect has been related to the reishi mushroom’s consumption. Conversely, there is scientific research that leads us to consider reishi as a useful product for allergies. (Reishi & allergies, published investigations)
See also: 3 key points to choose a good reishi product – Reishi consumption: When, How and how much?
1 - Figlas D, Curvetto N. Medicinal mushroom reishi (Ganoderma lucidum). Main toxicity and allergenicity studies. Dosage, Posology and Side effects.
2- Pan, D., et al., Isolation and characterization of a hyperbranched proteoglycan from Ganoderma lucidum for anti-diabetes. Carbohydr Polym, 2015. 117: p. 106-14.
3- Tie, L., et al., Ganoderma lucidum polysaccharide accelerates refractory wound healing by inhibition of mitochondrial oxidative stress in type 1 diabetes. Cell Physiol Biochem, 2012. 29(3-4): p. 583-94.
4- Wang, C.W., J.S.M. Tschen, and W.H.H. Sheu, Ganoderma lucidum on metabolic control in type 2 diabetes subjects - A double blinded placebo control study. Journal of Internal Medicine of Taiwan, 2008. 19(1): p. 54-60.
5- Bhardwaj, N., P. Katyal, and A.K. Sharma, Suppression of inflammatory and allergic responses by pharmacologically potent fungus Ganoderma lucidum. Recent Pat Inflamm Allergy Drug Discov, 2014. 8(2): p. 104-17.
6- Mizutani, N., et al., Effect of Ganoderma lucidum on pollen-induced biphasic nasal blockage in a guinea pig model of allergic rhinitis. Phytother Res, 2012. 26(3): p. 325-32.