It May Be Time to Reconsider How We Care for the “Kidneys”
I started playing soft tennis when I was in middle school. During high school, I was fortunate enough to compete at the national high school championships and the National Sports Festival of Japan, spending every day on the court. Even now, whenever I find the time, I still pick up my racket.
Thankfully, I have never experienced any major injuries to my lower back or knees. But having played for so many years has also made me aware of small changes in my body.
The stiffness that used to disappear after a good night’s sleep can now linger into the following day. On winter mornings, my body feels stiffer when I first start moving, and I sometimes feel that I have slightly less strength and resilience when I need to brace myself.
Rather than simply dismissing these changes as part of getting older, I have gradually come to think of them as possible signals from my body.
A Traditional Eastern Perspective on Lower Body Health
Studying medicinal food therapy changed the way I look at these signals. I learned that, when considering the health of the legs and lower back, traditional Eastern medicine places particular importance on the Kidneys and Liver.
In my medicinal food classes, I often hear similar comments from students:
“Lately, the stairs have become so difficult that I find myself looking for an escalator.”
“My knees bother me so much that I can no longer sit in the traditional kneeling position.”
“I don’t recover from tiredness as quickly as I used to.”
Everyone tends to attribute these changes simply to age. But perhaps, rather than being a matter of age alone, it may be that the body’s foundation is simply becoming a little tired.
The Role of the Kidneys: Storing Vital Energy and Nourishing Bones
In traditional Eastern Asian medicine, the lower back is described as the “palace of the Kidneys.”
The Kidneys are traditionally regarded as the place where Jing, or the body’s vital essence, is stored. They are associated with nourishing the bones and marrow, and are also considered closely connected with the hair, ears, teeth and bladder.
An increase in grey hair, needing to use the toilet more frequently, or changes in hearing may therefore be understood, within this traditional framework, as messages from the Kidneys.
The Yōjōkun (The Book of Life-Nurturing), written by Kaibara Ekken, who lived to the age of 83 during Japan’s Edo period, also contains teachings that ageing begins in the legs and lower back, and that caring for the feet and legs each day, moderating food and drink, and keeping the body active are important paths to longevity.
In Japan, caring for the legs and lower back has therefore long been regarded as an important part of maintaining health.
The Role of the Liver: Nourishing Muscles and Storing Blood
The other key organ is the Liver.
In traditional Kampo medicine, the Liver is said to store Blood and nourish the muscles, helping them maintain their flexibility.
Muscle stiffness, a tendency to develop cramps, or nails that break easily may, according to this traditional framework, be signs that the Liver’s Blood is insufficient.
The Kidneys, which support the bones, and the Liver, which nourishes the muscles and tendons, are considered to support one another. This relationship is known as “Liver and Kidney sharing the same source”.
Rather than caring for one alone, it is therefore important to nourish both together.
Three Everyday Habits for Long-Term Vitality
The things I personally make a point of doing in everyday life are not particularly complicated.
First, I try to rest by 11 p.m. whenever possible. According to traditional Eastern medicine, the period between 11 p.m. and 3 a.m. is considered a time when Blood returns to the Liver and the Kidneys store Jing. The more tired I am after playing tennis, the more I try to go to bed early.
Second, I try not to let my body become cold. I make it a point to keep the key cold-sensitive areas—my neck, wrists, ankles, abdomen, and lower back—warm all year round. Even in summer, wearing a simple abdominal wrap can help protect the Kidneys, according to traditional Eastern medicine.
Third, I try not to remain in the same position for too long. Traditional Eastern Asian medicine has the expressions “standing for too long harms the bones” and “sitting for too long harms the muscles.”
These teachings remind us that remaining standing or sitting for prolonged periods can place strain on the bones and muscles.
Even between tennis sessions, I rotate my ankles and repeatedly raise and lower my heels, paying attention to keeping things moving.
The eyes are traditionally considered to be connected with the Liver, so I also try to avoid looking at my smartphone for too long and make a point of looking into the distance from time to time.
Nourishing Ingredients and a Simple Recipe
When it comes to food, I consciously look for ingredients that are readily available at the supermarket—particularly black-coloured foods, seeds and foods with a naturally sticky texture.
Black beans, black sesame seeds, hijiki seaweed, Chinese yam, walnuts and goji berries have traditionally been considered nourishing for the Kidneys and Liver, and have long been valued in Japan.
One of my recommendations is black bean and Chinese yam miso soup.
Simmer soaked black beans and diced Chinese yam in a kombu broth. Once you turn off the heat, dissolve in the miso. Finish with a spoonful of freshly ground black sesame seeds.
The comforting sweetness and gentle texture of the ingredients make this a warming and reassuring dish from the perspective of traditional food therapy.
If you choose domestically grown organic black beans and naturally brewed miso, I also feel that the care put into selecting these ingredients can be gentle on both body and mind, while naturally conveying something of Japan’s long tradition of careful, thoughtful craftsmanship to customers overseas.
Supporting Health for the Years Ahead
Growing older does not necessarily mean simply becoming weaker.
It can also mean becoming more able to hear the messages coming from your own body.
Today, warm yourself. Go to bed a little earlier. Add one nourishing ingredient to your meal.
I believe that these small acts of nurturing and caring for your health, when continued over time, can help support the strength of your legs and lower back for the years to come.
Miho Iwami
International TCM Medicinal Diet Specialist