Milk Thistle for Women's Health

 

    Milk thistle or Silybum marianum has been known as one of the medicinal plants commonly used for liver health. The pharmacologically relevant actions of milk thistle for liver diseases include anti-inflammatory, immunomodulating, antifibrotic, antioxidant, and liver-regenerating properties. It has clinical potential in patients with alcoholic liver disease, nonalcoholic fatty liver disease, viral hepatitis, drug-induced liver injury, and mushroom poisoning. The overall literature data suggest that that the animal study data are very encouraging, however, further well-designed randomized clinical trials in humans are needed to fully substantiate the real value of milk thistle preparations in liver diseases (1-2).

 

    Beyond its liver protective properties, milk thistle has been studied for potential benefits for women's health, such as reducing menopausal symptoms. The reduction in estrogen levels during menopause may cause a range of symptoms of varying severity that affect the quality of life, such as hot flashes, night sweats, sleep disturbances, fatigue, depression, and reduction in libido. Although hormone replacement therapy has been used for years to relieve menopausal symptoms, recent studies have raised concerns regarding its safety, especially in women with a personal or family history of breast or uterine cancer or other estrogen-dependent cancers, and women with or at risk of cardiovascular disease. As a result, the tendency to use herbs to manage menopausal symptoms has increased in recent years.

 

    One study evaluated the effect of milk thistle compared with placebo in women with hot flashes. Eighty women were randomly allocated into two equal groups (milk thistle extract [400 mg/d] or placebo capsules). Hot flashes frequency and severity were evaluated in 12 weeks with the Greene Climacteric Scale (GCS) and the Hot Flush Related Daily Interference Scale (HFRDIS)(3).

 

    The frequency of hot flashes in the experimental group decreased from 4.32 ± 0.20/day before the intervention to 2.05 ± 0.16 and 1.34 ± 0.17/day, respectively, at the fourth and eighth weeks of the intervention, and to 1.31 ± 0.15/day in fourth-week follow-up after the end of the treatment. The differences in means were statistically significant (p < .001) before the intervention and in the fourth, eighth, and 12th weeks after it. In the placebo group, hot flashes frequency was 3.60 ± 0.21/day, 3.48 ± 0.17/day and 3.34 ± 0.17/day before and 4 and 8 weeks after the treatment, respectively, and 4.05 ± 0.16/day 4 weeks after the end of treatment with no significant differences (p > .05)(3).

 

    The severity scores of hot flashes in the milk thistle group were 5.25 ± 0.22, 2.55 ± 0.95, 1.70 ± 0.09, and 1.62 ± 0.08, respectively, before the intervention and at the fourth, eighth and 12th week after it. The reduction in severity scores was significant (p < .001) while in the placebo group severity had a nonsignificant decrease from 4.85 ± 0.11 to 4.70 ± 0.19 and 4.62 ± 0.20 along 2 months but 1 month after the end of treatment it increased to 5.60 ± 0.09. Comparing the results showed that there was a significant difference in the severity and frequency of hot flushes between the two groups during and after treatment (p < .001)(3).

 

    Not only did hot flashes frequency and severity decreased during the study in the test group which was significantly better than the effects of placebo in all steps of the study (p < .001), but significant decreases in GCS and HFRDIS scores were also detected in milk thistle group compared with placebo after 4, 8 and 12 weeks (p < .001). The results showed that milk thistle can decrease the frequency and severity of hot flashes significantly. Considering the safety and high consumption of this herbal medicine worldwide, its use in women with menopausal symptoms can be helpful (3).

 

    In a previous randomized, double-blind, placebo-controlled trial in 50 healthy pre and postmenopausal women (aged 44-65 years), an oral Phyto-Female Complex (includes milk thistle) or matched placebo was prescribed twice daily for 3 months.  The Phyto-Female Complex included standardized extracts of black cohosh, dong quai, milk thistle, red clover, American ginseng, and chaste-tree berry (4).

 

    The women receiving Phyto-Female Complex reported a significantly superior mean reduction in menopausal symptoms than the placebo group. The effect of treatment improvements in menopausal symptoms increased over time; by 3 months there was a 73% decrease in hot flashes and a 69% reduction in night sweats, accompanied by a decrease in their intensity and a significant benefit in terms of sleep quality. Hot flushes ceased completely in 47% of women in the study group compared with only 19% in the placebo group. There were no changes in findings on vaginal ultrasonography or levels of relevant hormones (estradiol, follicle-stimulating hormone), liver enzymes, or thyroid-stimulating hormone in either group. This Phyto-Female Complex was considered safe and effective for the relief of hot flushes and sleep disturbances in pre-and postmenopausal women, at least for 3 months' use (4).

 

    The effect of milk thistle on the symptoms of menopause such as hot flashes can be interpreted from different perspectives. Phytoestrogens, as estrogen-like phytochemicals, are known to be one of the most important plant compounds in reducing the symptoms of menopause. Although milk thistle is not classified as a significant phytoestrogen, some studies showed that it can affect gonadal hormones' receptors resulting in its neuroprotective and antiosteoporotic effects. Silibinin, an active component of milk thistle, has been shown to affect the estrogen receptor β expression levels in breast cancer cells as well. Also, clinical findings about its galactagogue activity and ovulatory effect in women with PCO show its effect on female sex hormones. Serotonergic and noradrenergic pathways and opioid receptors are other involved pathways in hot flushes which may be modulated by milk thistle. The effect on these receptors can also justify the good effect of milk thistle on improving sleep, mood, and other aspects of psychological condition (3).

 

    Milk thistle is known to act as an antioxidant by reducing free radical production and lipid peroxidation, has antifibrotic activity, and may act as a toxin blockade agent by inhibiting the binding of toxins to the hepatocyte cell membrane receptors. While the benefit of reducing menopausal symptoms is less known, the clinical studies in the women showed milk thistle as a promising dietary supplement for women's health.

 

References:

1. Abenavoli L, Capasso R, Milic N, Capasso F. Milk thistle in liver diseases: past, present, future. Phytother Res. 2010 Oct;24(10):1423-32. doi: 10.1002/ptr.3207. PMID: 20564545.

2. Abenavoli L, Izzo AA, Milić N, Cicala C, Santini A, Capasso R. Milk thistle (Silybum marianum): A concise overview on its chemistry, pharmacological, and nutraceutical uses in liver diseases. Phytother Res. 2018 Nov;32(11):2202-2213. doi: 10.1002/ptr.6171. Epub 2018 Aug 6. PMID: 30080294.

3. Saberi Z, Gorji N, Memariani Z, Moeini R, Shirafkan H, Amiri M. Evaluation of the effect of Silybum marianum extract on menopausal symptoms: A randomized, double-blind placebo-controlled trial. Phytother Res. 2020 Dec;34(12):3359-3366. doi: 10.1002/ptr.6789. Epub 2020 Aug 6. PMID: 32762030.

4. Rotem C, Kaplan B. Phyto-Female Complex for the relief of hot flushes, night sweats and quality of sleep: randomized, controlled, double-blind pilot study. Gynecol Endocrinol. 2007 Feb;23(2):117-22. doi: 10.1080/09513590701200900. PMID: 17454163.

 

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