The world is moving fast. Many people have daily lives that demand too much in too little time. Technology and social media have people plugged in day and night. Speed limits on highways are faster, bullet trains speed from city to city in countries across the world, and people rush from one place to another day after day. All of this can burn the yin, deplete the kidney qi, and not only leave one depleted, but also leave one susceptible to deeper immune-based diseases that result from such a depleted state.
If you don’t already know the Scrophulariaceae family plant, Rehmannia glutinosa, commonly known as Chinese foxglove root, perhaps this introduction will open your awareness to an herb with a focus on replenishing kidney deficiency, especially kidney yin. When we speak of kidney deficiency in Chinese medicine, the broader interpretation includes adrenal deficiency, which can influence the immune system and the expression of both allergic and autoimmune pathologies.
Rehmannia and Yin Deficiency
Knowledge and understanding about rehmannia comes from the Traditional Chinese Medicine (TCM) materia medica, which includes two preparations: raw rehmannia, called Sheng Di Huang, and prepared rehmannia, called Shu Di Huang. Both raw and prepared rehmannia nourish yin and blood; however, the raw sheng di huang is used more to dissipate heat, allowing the body to generate more fluids, while the prepared shu di huang is used more to nourish the body when deficiencies of yin qualities of cool and moist result in too much heat or dryness in the system.
Raw rehmannia, sheng di huang, is energetically cold, sweet, and bitter. It works in the heart, kidney, and liver channels. Raw rehmannia nourishes the yin and the blood and generates fluids, countering the dry expression of yin deficiency. Dry symptoms indicating yin deficiency are seen in menopause with dry hair, skin and dry vagina, as well as in autoimmune conditions like Sjogrens syndrome with dry mouth, dry eyes, and the sicca complex. Raw rehmannia, with its bitter energy, is antipyretic, clearing heat and cooling the blood. It is useful in high fevers and in cases of bleeding or hemorrhaging when too much heat in the blood drives excessive blood loss. Symptoms of insomnia, irritability, low grade fevers, mouth and tongue sores, and malar rashes can indicate excess heart fire.
Prepared rehmannia, shu di huang, has been cooked in wine, rendering its energy sweet and warming. It also works in the heart, kidney, and liver channels, and is said to tonify the blood and nourish the yin. This is needed when there is deficient blood with symptoms of dizziness, light headedness, palpitations, and insomnia. Prepared rehmannia is used as a tonic during pregnancy and after excess menstrual bleeding or postpartum bleeding.
Clinically, kidney yin deficiency presents as adrenal fatigue and adrenal exhaustion. It is especially prevalent in perimenopausal and menopausal women who have worn out their adrenal glands throughout their lives, and, as they move into menopause, don’t have the support of estrogen production from the adrenals. Fatigue can be the presenting symptom, but beneath that are yin deficiency symptoms, such as insomnia, night sweats, premature gray hair, aching low back pain, joint pain, loss of libido, and skin, hair, and vaginal dryness.
For men, erectile dysfunction and nocturnal emissions can go hand-in-hand with adrenal issues. In these cases, Rehmannia glutinosa, along with adrenal support, will be the most effective treatment. I like to combine rehmannia with licorice (Glycyrrhiza glabra), and add other herbs to this base.
The Chinese physician Zhang Jingyue (1563-1640) observed that, during his lifetime, most diseases involved yin deficiency. He specialized in rehmannia-based formulas. His writing stated, “Rehmannia is needed to guard the yin in cases of deficiency that involve scattering of the spirit; the heaviness of rehmannia is needed to counter the rising fire of yin deficiency; the calming quality of rehmannia is needed for pacifying the agitation of yin deficiency; the mild sweetness of rehmannia is needed for relaxing the impulsive nature of yin deficiency; rehmannia is needed to restrict the flooding of water evil in cases of yin deficiency; rehmannia is needed to retrieve the scattered genuine qi back to its origin in the kidney.”
Classic Rehmannia Formulas
In the TCM tradition, herbs have always been administered in formulas in order to balance any extremes of an individual herb. In the case of rehmannia, it has a heavy, dense energy, especially the prepared rehmannia, so it is often given in formulas with herbs to lighten and disperse the heaviness.
Rehmannia Six Formula
Liuwei Dihuang Wan, is made up of 3 herbs that warm and nourish 3 different organs, as well as a cooling and dispersing herb to pair with each for balance:
Rehmannia glutinosa and Alisma plantago-aquatica restore the kidney yin and normalize kidney function
Cornus officinalis fruit and Paeonia suffruticosa improve liver function, which provides moistening action to the kidneys
Dioscorea opposita and Poria cocos improve spleen function, thereby increasing nutrients and nourishing the blood, which improves liver health.
Rehmannia Six Formula improves digestion and regulates sugar metabolism, and is often given in malabsorption, failure to thrive, and diabetes mellitus. It is beneficial for the immune function, which is closely linked to the health of the digestive tract. Being a kidney tonifying herb, it addresses urogenital disorders, including chronic glomerulonephritis and urinary tract infections. By enhancing cardiac function, it reduces hypertension. Vision problems, especially diminishment of close up vision, and other symptoms of aging are linked to kidney yin deficiency and are supported with Rehmannia Six Formula.