The Power of Vitamin D: From Osteoporosis to Cancer - Medical Frontiers

Join us as we explore medical frontiers. Vitamins are crucial for our health. Among them, vitamin D is unique as it is produced when the body is exposed to sunlight. While its role in strengthening bones has been known for quite some time, there was limited understanding of the way it worked. Japanese researchers uncovered the mechanism and captured unprecedented footage of the process. Vitamin D is now attracting attention for its ability to raise survival rates among cancer patients. In 2023, a study by another Japanese research team gained global recognition as a game changer for vitamin D and cancer. Mmm, this feels so nice. I also try to bask in the sunlight whenever I can. But how about you? Are you getting your daily dose of vitamin D? Reports suggested about 98% of Japanese don't have adequate levels of vitamin D. And there are concerns that this may lead to a number of different health issues. We're going to delve into the latest Japanese research to uncover the benefits, significance and the potential of vitamin D. The International Osteoporosis Foundation estimates that over 200 million people worldwide have the bone weakening disease. Osteoporosis occurs when bones become porous and fragile with age. Bone fractures happen globally every three seconds. In severe cases, patients may become bedridden and face complications. Vitamin D is critical in maintaining healthy bones. Hello, doctor. Hello. Nice to meet you. Nice to meet you, too. To understand the effects of vitamin D on the body, we spoke with Naoko Tsugawa, a director at the Vitamin Society of Japan. What are the characteristics of vitamin D? Vitamin D is one of the 13 vitamins in the body. It is one of the 4 vitamins that is easy to dissolve in oil. The main function of vitamin D is to increase the calcium concentration in the bloodstream. It serves to maintain the calcium balance. Calcium is the most important organ of the bone. So how and where is vitamin D specifically made in the body? Direct exposure to ultraviolet rays causes a change in a substance found in the skin's outer layer, eventually converting it to vitamin D. The vitamin then enters the body through tiny blood vessels known as capillaries. Vitamin D is also contained in fish and other foods. But regardless of its source, vitamin D does not function in its original state. It undergoes a change in the liver, then travels in the bloodstream. If needed, it goes through another transformation in the kidneys, becoming activated before it can work on bones and other tissues. For a long time, little was known about how vitamin D strengthens bones. A breakthrough occurred through the efforts of a Japanese research team led by Ishii Masaru. Bones undergo constant regeneration. Osteoclasts break down old bone, while osteoblasts repair and restore damaged areas. However, this balance is disrupted by the various effects of aging. When bone breakdown becomes dominant, bones turn increasingly weak and porous. This is osteoporosis. Using mice, Ishii captured footage of osteoclasts breaking down bone tissue for the first time in the world. The blue areas are bone, and the red parts, resembling amoebas on the bone's surface, are osteoclasts. The osteoclasts emit a glowing green acid as they break down the bone tissue. We found out that vitamin D is effective against osteoclasts. Osteoclasts are made from a type of macrophage that specializes in consuming bone tissue. This macrophage moves from the bloodstream to the bone's surface, eventually becoming an osteoclast. The movement of this macrophage is regulated by two types of receptors. When one type is activated, the macrophage travels to bones, becoming an osteoclast. Activation of the other type redirects the macrophage back to the bloodstream. The tug-of-war between these two receptors regulates the movement of the macrophage. However, any imbalance causing too many of these macrophages to move to bones results in an increased number of osteoclasts. This is where vitamin D comes in, using its power to prevent the successive migration. Ishii captured the process in an experiment. The round objects moving around on the bone are macrophages before they become osteoclasts. When the active form of vitamin D is added, the macrophages start moving toward the blood vessel. There is a clear difference when compared with the absence of active vitamin D. Vitamin D is a new treatment or preventative measure. We can now determine the benefits of vitamin D by studying its properties. Vitamin D is not just a good source of vitamin for our bones, but also a good source of vitamin for our health and prevention. In recent times, an increasing number of people have not been getting enough vitamin D. Sugawa's research shows that about 60% of Japanese adults are deficient, which poses a serious health risk. What's causing this huge deficiency of vitamin D? Vitamin D deficiency isn't limited to people in Japan. While the figure varies depending on region and age, it's estimated that up to 70% of Europeans are lacking in the nutrient. The work style has changed so much in the last three years. People are working from home, you know, they're not getting it, they're in front of their screens the whole day. So I think it's always like a recipe for vitamin D deficiency, the way we're living our lives. I'd like people to come up with a recipe for vitamin D deficiency. Vitamin D also has the potential to prevent cancer recurrence and improve survival rates. In August 2023, a research team led by pediatric oncologist Urashima Mitsuyoshi published a groundbreaking discovery that drew attention worldwide. Urashima's interest in vitamin D was sparked by a research paper on macrophages. Can you take a look at this image? This is where macrophages eat blood vessels. In the past, when there was no antibiotics, patients who were infected with blood vessels had to go on a day-to-day basis. That was one of the keys to improving survival rates. After 100 years, we finally understood the mechanism. Until then, vitamin D was just a bone. It wouldn't work on infections or cancer. That was my initial thought. But when I saw this, I was like, wait a minute. Humans have been alive for a long time. We've been alive since the days when there was no vaccine, and we're still alive even without antibiotics. So if we don't have a mechanism like this, it won't work. That's how I changed my mind drastically. After learning that vitamin D stimulates the immune system, Urashima thought it might also be effective against cancer. In 2010, he launched a clinical trial called the Amaterasu Trial. The project was named after Amaterasu Ōmikami, a goddess in Japanese mythology associated with the sun, which helps to produce vitamin D. The clinical trial involved 417 patients with digestive tract cancer. They were divided into two groups. One received vitamin D supplements, and the other a placebo. Starting about 2 weeks after surgery, each group took 2 capsules daily. Recurrence and death rates were monitored for up to 8 years. The results showed that the vitamin D group had a higher proportion of patients who remained recurrence-free for 5 years. However, this data wasn't recognized as significant, possibly due to the small number of participants. Therefore, Urashima took part in a joint international study on the relationship between cancer and vitamin D. It analyzed data from 100,000 people in countries including the United States and Germany. The study found that vitamin D supplements led to a 12% increase in the survival rate, regardless of cancer type. To find more conclusive evidence, Urashima further analyzed the data from the AMATERASU trial. He found that vitamin D is especially effective for patients with mutations in a protein called P53. The P53 protein is present in cells and plays a central role in protecting our bodies from cancer. When a cell is damaged, P53 pauses its growth to repair it. This prevents abnormal cells from multiplying. In cases of severe damage, P53 issues a command to initiate apoptosis, a process in which cells self-destruct. This protein acts as a brake that prevents cells from turning cancerous. However, stressors such as smoking, radiation and chemicals can cause mutations in P53, which can disrupt the brake mechanism, leading to uncontrolled growth of abnormal cells and eventually to cancer. About half of cancer patients have mutations in P53. Urashima focused on people with P53 mutations and antibodies against the protein in their blood. He compared those taking vitamin D and the placebo, then checked their recurrence and death rates. The green line represents the vitamin D group and the gray line the placebo group. At first, there was almost no difference between them. But after about a year, a large gap began to appear. Five years later, 80% of those in the vitamin D group remained cancer-free. Urashima speculates that once vitamin D enters cancer cells, it stops the erratic behavior of mutated P53 or triggers apoptosis in these cells. To study the connection between vitamin D and P53 mutations in more detail, Urashima is conducting a new clinical trial involving eight types of cancer. We asked Sugawa how much vitamin D we need. She says the recommended daily amount is 15 to 20 micrograms. In summer, 10 to 30 minutes outdoors without sunscreen provides about 10 micrograms of vitamin D, depending on skin type, exposed skin area and geographical location. In winter, it may take about one hour for the same amount. If you wear sunscreen, exposing uncovered palms is one way to get sun exposure. As for food sources, salmon, dried sardines and whitebait and fish liver are rich in vitamin D. A slice of salmon, for instance, has about 40 micrograms of vitamin D. Sugawa says eating one every two to three days can help to maintain a stable level of vitamin D Vitamin D is also present in mushrooms such as shiitake, maitake and wood ear. Since it's fat-soluble, consuming it with fatty foods can improve its absorption. So in that case, is there any points that we should be really cautious of when taking vitamin D? If you take too much vitamin D, it can lead to hyperlipidemia. Hyperlipidemia is a type of hypercalcium deficiency. When hypercalcium levels in the blood rise, it can cause a deterioration of the blood vessels and cause life-sustaining disorders. This can lead to death. So we should avoid taking such dangerous supplements. If you are on medication, consult your doctor to determine whether it's safe to take supplements. Thank you so much for your time today. Thank you. Our instructor is Nancy Singleton Hachisu from California, who now lives in Japan. Since marrying a Japanese farmer 35 years ago, Nancy has been exploring the breadth of Japanese cuisine. The first dish is grilled shiitake topped with grated Japanese daikon radish. Kind of a throwback to the stuffed mushrooms of my mother's generation. In Australia, my mom used to, yeah, a lot of stuffed mushrooms. These you mound grated daikon that has some shiso and the stems in it. The stems in there as well. So not to waste. I've dried them outside for about an hour just to sort of boost the vitamin D. When using fresh shiitake mushrooms, expose them to sunlight for about an hour before cooking them. This extra step boosts their vitamin D content. It's important to dry them upside down. The cap's underside contains a significant number of substances that turn into vitamin D when exposed to sunlight. Okay, shall we go? Yep, absolutely. Sounds great. Preheat an iron pan and grill the shiitake sprinkled with a pinch of salt for about three minutes. Okay, we want this to be fragrant. So you can stir this every once in a while. Chop the stems and roast them, stirring until fragrant. Shiitake, they have such a different flavor profile to all the other mushrooms. Yeah, exactly. This is getting quite fragrant, I think. So we're going to make the topping now. Yes. Finely chop some shiso leaves and combine them with the roasted shiitake stems and the grated daikon. Put the mixture on the grilled shiitake. Drizzle a blend of kombu dashi stock, light taste soy sauce, and mirin. Such a beautiful appetizer. Shall we taste it? Absolutely. Okay. With that dashi and with that shiso, with the combination of the shiso and the grated, fabulous. Wow. Very healthy and very delicious and very easy. Are you ready to go, Erica? I am indeed. So what's the next recipe with shiitake? Okay, cucumber shiitake in sesame vinegar. Ready? This recipe calls for dried shiitake. Soak them in hot water for about 30 minutes to rehydrate them. Simmer the shiitake in a broth made from the soaking liquid, soy sauce, and mirin. Then let it cool to allow the shiitake to soak up the flavors. We do a light salt in Japan, right? So this is like a quarter teaspoon. And I don't massage it. I lightly, I lightly toss it. Because I think there's always that technique in Japan of massaging. Toss sliced cucumber with salt and let it sit for about 10 minutes to extract moisture and soften it. The key to this recipe is sesame seeds. Grind roasted white and black sesame with a mortar and pestle to bring out the aroma. Mix the drained cucumbers and shiitake with the sesame seeds and vinegar dressing to finish. Itadakimasu. It has a really delicious crunch. Amazing texture. I love the vinegar. They're attached together, that's why. Oh, yum. Give it more. Definitely another helping of this. The third dish is a simmered shiitake and sweet potato. This recipe also uses dried shiitake. To enhance the flavor, we'll add chaotzai, a pickled Chinese vegetable with a sour and spicy taste. Put the ingredients in a pot containing chicken stock, rehydrated shiitake liquid, and salt, and simmer over medium heat for about 7 minutes. Oh, wow. This is fabulous. Chaotzai. I think it goes really well with shiitake. But the shiitake is really key. Shiitake has been popular for a really long time in the U.S., for sure. But raw shiitake. Dried shiitake is less popular. I think in Australia, too, it's really, really difficult to get hold of dried shiitake. If you can get fresh now in the supermarket, you couldn't probably 15, 20 years ago, but now you can. I have to say, all of the shiitake recipes, I have a new love now. So, Nancy, thank you so much. Thank you. Thank you for coming in. Thank you.