Is it actually true that diuretics will help reduce bloating due to period?

Yes they can help.: Bloating prior to or during your period is due to fluid retention & slower digestion (constipation). To decrease bloating avoid salt intake (including prepackaged foods), increase water intake (to flush the body & reduce constipation), consider magnesium or calcium supplements (with your dr’s approval) or otc meds that include a diuretic such as midol. Exercise and birth control pills may help.