Page 15 - Today's Dietitian (March 2020)

dose-dependent manner with lower risk of breast cancer in Products on the Market
both pre- and postmenopausal women. 9 There’s an array of mushroom-derived dietary supplements
There’s also significant interest in mushrooms as a treatment on the market. According to Wasser, mushroom supplement
for liver cancer, especially hepatocellular carcinoma. Test tube options include fruit body powders or fruit body extracts made
experiments as well as studies in mouse models have shown from either artificially cultivated or naturally grown mush-
that polysaccharides and other compounds extracted from var- rooms. Other supplements may consist of mushroom spores
ious species of mushrooms inhibit liver cancer cell proliferation or of dried and pulverized preparations of mushroom mycel-
and suppress tumor growth and metastasis, among other ben- lium as well as substrate (the substance in which the mush-
eficial actions. 7 room grows). Most of the mushrooms used for production of
Research also suggests that certain kinds of mushrooms may dietary supplements are commercially grown, not gathered in
be effective against other types of cancers, including uterine the wild, to guarantee proper identification and purity of the
cervical cancer, bladder cancer, leukemia, and gastric cancer. 7 product, Wasser says.
On a cautionary note, however, a prospective study of two large Supplements are available in a variety of forms, including
US cohorts published in 2019 found no association between tablets, hard capsules, soft capsules, tinctures, and granules.
mushroom consumption and either total cancer incidence or Some supplements contain only a single mushroom vari-
incidence of site-specific cancers, suggesting the need for addi- ety, while others contain a combination. Some of the more
tional research to tease out the precise impact of specific mush- common species that appear in supplements are Ganoderma
rooms on various cancers in different population groups. 10 lucidum (lingzhi or reishi), Lentinus edodes (shiitake), Grifola
frondosa (maitake), Cordyceps (caterpillar mushrooms), Tram-
Cognition and Neurodegenerative Disease etes versicolor (turkey tail), lion’s mane, and Inonotus obliquus
An experiment in mice found that mushrooms enriched with (chaga). The proper dosage of each supplement is controversial,
ergocalciferol protected against beta-amyloid peptide toxic- Wasser says, and it varies significantly depending on both the
ity in the brain and against mild cognitive impairment, both form (eg, capsules, tincture) and the formulation. Tradition-
of which are precursors to dementia. In human populations, ally, however, the standard daily dose of mushroom biomass is
epidemiologic studies in Singapore and Japan have found that equivalent to 100 to 150 g of fresh mushrooms.
mushroom consumption is associated with reduced risk of mild In Wasser’s view, mushroom supplements shouldn’t be
cognitive impairment and dementia. 11,12 Clinical trials are lim- viewed as a substitute for modern medicine, but they do
ited, but one small trial in elderly Japanese subjects found that hold value for disease prevention and can in some cases be a
oral administration of lion’s mane (Hericium erinaceus) mush- useful complement to modern medicine. Janet Zarowitz, MS,
room powder helped improve mild cognitive impairment. Pre- RD, CDN, a functional nutritionist in Briarcliff Manor, New
clinical evidence also suggests that mushrooms may offer York, agrees. In her view, RDs should consider recommending
protection against other neurodegenerative disorders, includ- mushroom-derived supplements both as a foundational
ing Parkinson’s disease. 13 support for the immune system in healthy people and as
According to Beelman, these effects likely are due in part to a complementary treatment for disease (especially for
4
the high levels of ergothioneine in mushrooms. Lower levels of individuals with cancer).
ergothioneine have been associated with increased risk of cog-
nitive decline and Parkinson’s disease. 14,15 By contrast, uptake Recommendations for RDs
of ergothioneine in the brain appears to decrease oxidative To evaluate the efficacy of specific mushroom species for a
stress, which may reduce symptoms of neurological disease. 16 particular therapeutic purpose or to check safety concerns,
Zarowitz recommends starting with the Therapeutic Research
Cardiometabolic Disease Center’s Natural Medicines database. When recommending
Both preclinical and clinical studies suggest that mushroom mushroom supplements to cancer patients or for treatment of
consumption may help to protect against obesity, heart dis- other specific diseases, she encourages RDs to beware of poten-
ease, and type 2 diabetes. 17,18 Various studies in test tubes, tial interactions with medications. “I need to see what other
animal models, and human subjects have suggested that treatments the patient is on. I work with the oncologist to make
mushrooms can reduce inflammation, cholesterol, blood pres- sure it doesn’t compete with a chemotherapy,” Zarowitz says.
sure, and blood glucose, and can block the formation of fatty If using fresh mushrooms rather than supplements, cook
plaques in the arteries. 7,19-27 These effects have been linked to them. “Mushrooms are a great functional food that can help
various bioactive compounds in mushrooms, including beta- promote health and be an adjunct therapy for certain diseases,
glucans and other polysaccharides as well as ergothioneine. 17,18 but they must be cooked to get all these benefits,” Zarowitz
Although not a study of mushrooms per se, a large long-term says. Finally, she adds, “mushrooms can concentrate toxins, so
observational study from Sweden published in 2019 found you want to make sure the source is organic.” n
that higher levels of ergothioneine, which is found primarily in
mushrooms, were associated with a significantly lower risk of Jamie Santa Cruz is a freelance writer of health and medical topics
28
cardiometabolic disease and mortality. On the other hand, based in Parker, Colorado.
another 2019 study, this one a large prospective study of more
than 100,000 US adults, found no association between mush- For references, view this article on our
room consumption and risk of CVD, stroke, or type 2 diabetes, website at www.TodaysDietitian.com.
demonstrating the need for additional research in this area. 29
MARCH 2020 • WWW.TODAYSDIETITIAN.COM 15