Korea Spends Over ₩220 Trillion a Year on Healthcare — Without Preventive Medicine, a National Crisis Looms

Dr. Lee "Now that everyone has arrived, let's begin our class. As I mentioned last time, today we'll look at the effects of the ketogenic diet on dementia—our second session on its therapeutic benefits. Both developed and developing countries are aging rapidly, and Korea is no exception. Healthcare costs are climbing steeply, and forecasts say the trend will only worsen. This burdens families, but it also drives national debt, so individuals and governments alike are wrestling with the issue. To put it in perspective, in 2023 the Korean government's budget was about ₩638 trillion, while current health expenditure—public plus private—reached ₩221 trillion, which is 34.6% of the budget (Table 6-1)."

Emily "That's astonishing. I had no idea. ₩638 trillion against ₩221 trillion—almost a third of the budget going to healthcare. That must be why our taxes keep rising and household budgets keep tightening. It's really concerning."

Dr. Lee "Yes, the situation is serious. The good news is that, according to recent research, aging and disease are not inevitable. Improving lifestyle—especially diet—prevents many diseases and can even reverse some of them. A healthy diet supports a healthy old age and a meaningful life. We sometimes hear stories of people who stay vigorous until just days before they pass away, which only confirms how important lifestyle change is. In particular, a wealth of scientific studies report that plant-based eating, combined with a ketogenic ratio that prioritizes healthy fats, has favorable effects on human health. And research shows that a plant-centered diet and a ketogenic diet have very positive effects on the prevention and improvement of senile dementia. Today I'll introduce several studies, including some published in Nature-family journals."

Zoe "Nature is the world's most prestigious journal—the fact that the ketogenic diet appears there raises my expectations.^^"

"Ketogenic Diet Enhances Neurovascular Function with Altered Gut Microbiome in Young Healthy Mice" (Ma et al., 2018)

Dr. Lee "The first study is an experimental paper from the Nature family, published in 2018. The title is "Ketogenic diet enhances neurovascular function with altered gut microbiome in young healthy mice" (Ma et al., 2018). You can search the title online and read the original."

Everyone is busy taking notes.

Dr. Lee "The blood vessels that supply nutrients and oxygen to neurons play a decisive role in cognition and mental health. As you know, the brain is only 2% of body weight but uses 20% of our oxygen and energy. Cerebral blood vessels make this possible. If you look at an image of brain vasculature, you'll see a dense web of microvessels filling the entire brain. Different brain regions handle different functions (Figure 6-1). When the vessels in a particular region fail, the corresponding function is impaired. Vascular problems also affect mood and emotion. Anxiety, depression, and dementia are all reported to be associated with reduced cerebral blood flow."

Susan "Doctor, I understand that cerebral vessels can affect cognition, emotion, and mood. What causes these vascular problems in the first place?"

Dr. Lee "A natural follow-up question. Brain dysfunction has many causes. The main ones include neuroinflammation, synaptic damage from external trauma, and genetically determined differences in neuronal architecture."

Grace "So the ketogenic diet shows positive effects on these various forms of cerebrovascular damage?"

Dr. Lee "Yes. Let me continue with the study. It's an animal experiment using mice. One group received a ketogenic diet, the control group a standard diet. Each group had 9 to 10 male mice. The ketogenic diet was 75.1% fat, 8.6% protein, 4.8% fiber, and 3.2% carbohydrate. The standard diet was 65.2% carbohydrate, 18.1% protein, 4.8% fat, and 2.9% fiber. Now a question: the ketogenic ratio places fat calories in the numerator and the sum of carbohydrate and protein calories in the denominator. What is the ratio for each diet?"

Emily (raises hand quickly) "I'll try. In the keto diet, fat is 75.1%, and protein 8.6% plus carbohydrate 3.2% gives 11.8%. So 75.1 ÷ 11.8 ≈ 6.3. The ketogenic ratio of the keto group is 6.3."

Zoe "Let me do the standard diet ^^ (everyone laughs). Carbohydrate 65.2% plus protein 18.1% equals 83.3%. Then 4.8 ÷ 83.3 = 0.09. But that seems extremely small."

Dr. Lee "Well done, both of you—correct. Zoe, you're right that 0.09 seems tiny, but the standard diet in this experiment matches the typical modern diet, which usually has a ratio around 0.08. Almost identical."

Zoe "Wow… really? Working through it numerically really brings home how much carbohydrate dominates our daily diet. When I think about it—bread, cookies, rice cakes, ramen, rice, noodles—almost everything I eat is carbohydrate."

Dr. Lee (laughing) "Right? Let me continue with the results. After 16 weeks on each diet, cerebral blood flow was measured. Figure 6-2 (left) shows the brightness-coded flow images. The keto group is noticeably brighter and the perfused area larger than the control. The right panel compares ventromedial-hypothalamus blood flow: the control averages 3.0, while the keto group reaches around 4.5—much higher."

Zoe "From the images, I can really feel that the keto diet promotes cerebral blood flow. But Doctor, what is the ventromedial hypothalamus, and why was that region measured?"

Dr. Lee "Good question. The ventromedial hypothalamus sits in the lower part of the hypothalamus.* It's involved in appetite regulation, sex drive, and aggression. The hypothalamus has been called the conductor of the hormonal orchestra. Our endocrine system runs on a three-tier arrangement—hypothalamus, pituitary, and peripheral endocrine organs—and the hypothalamus sits at the top, regulating dozens of downstream hormones (Figure 6-1)."

Zoe "Ah—so the keto diet and the carbohydrate-heavy standard diet affect appetite differently. The diversity of effects the keto diet has on the body really is fascinating."

Dr. Lee "Yes, indeed. And it influences the brain in many ways. Now let's turn to Table 6-2. The investigators measured mTOR—a protein that inhibits autophagy. When mTOR rises, autophagy is suppressed; when mTOR falls, autophagy proceeds. The carbohydrate-based control was set to 100, while the keto group was 71.1. This suggests autophagy runs more smoothly under the ketogenic diet."

Grace "mTOR is well known as the central regulator of cellular energy metabolism. So this study clearly shows the keto diet promotes autophagy by lowering mTOR. Remarkable."

Dr. Lee "Exactly. Next, the P-gp* result. Compared with the control at 100, the keto group reached 150.5—about 50% higher. P-gp is a glycoprotein transporter that pumps foreign substances out of various organs."

Emily "So the keto diet means more toxins and foreign substances are flushed out of cells in the body?"

Dr. Lee "Yes. As Emily put it, based on these results we can infer that the keto group clears foreign material from the brain more efficiently than the control. There was also a difference in endothelial nitric oxide synthase (eNOS**). Nitric oxide synthase dilates vessels and regulates the proliferation and division of vascular cells. The related image is in Figure 6-3 (left): compared with the control, the keto group's vessels are visibly brighter and thicker."

Susan "So you're saying the keto diet also helps vascular health? My husband has hypertension, so I've been worried about him."

Dr. Lee "Yes. The keto group's vessels appear brighter on imaging, and their eNOS production is higher—multiple lines of evidence converge on the same conclusion: the ketogenic diet supports vascular health."

"An Experimental Ketogenic Diet for Alzheimer Disease Was Nutritionally Dense and Rich in Vegetables and Avocado" (Aljobaily et al., 2022)

Dr. Lee "The next paper is "An Experimental Ketogenic Diet for Alzheimer Disease Was Nutritionally Dense and Rich in Vegetables and Avocado" (Aljobaily et al., 2022)."

Zoe "I love avocado too. When I make sandwich bento for lunch—I'm vegetarian—I use it often."

Dr. Lee "Yes. Avocado is known for its lipid content, so people on plant-based keto reach for it readily. This study examines whether a ketogenic diet incorporating vegetables and avocado is nutritionally adequate for older adults with Alzheimer's disease. The diet included MCT oil, butter, non-starchy vegetables, olive oil, avocado, nuts, and seeds. Excluded were potatoes, grains, red meat, and sugar-sweetened beverages. In terms of calories, fat was about 70%, protein 20%, and carbohydrate under 10%."

Grace "This study used MCT oil too. Medium-chain fatty acids really do seem to deliver good results in the body. Like grains, potatoes are high in carbohydrate and were excluded; among vegetables, the starchy ones were also excluded."

Dr. Lee "Yes. Some people avoid coconut oil or palm oil because of saturated fat, but that overlooks the medium-chain perspective. Grace, could you tell us about a few starchy vegetables? ^^"

Grace "Yes. Starchy vegetables include corn and root vegetables such as potato. In the West, they're often eaten as fried foods, which has been linked to weight gain. One report suggests that eating 100 g of starchy vegetables daily can add 2.6 kg over four years."

Dr. Lee "When weight rises and adipocytes enlarge, they secrete inflammatory adipokines (Figure 6-5). They also release reactive oxygen species and develop insulin resistance, which promotes diabetes. To return to this study: the authors first showed the diet was nutritionally adequate. As Figure 6-4 illustrates, intake of niacin, vitamin B12, selenium, phosphorus, riboflavin, and vitamin A exceeded the recommended levels. Calcium, vitamin E, folate, magnesium, and potassium came in around 70% of the recommended intake. Some may worry about calcium at 70% of RDA, but the recommended intake is set to cover the upper 97% of a population's requirement—it isn't the average. The average actually sits at about 70-80% of the RDA, and that range is safer because it minimizes the risk of overconsumption.

European countries like Sweden plan school meals at 70-80% of recommended intake, because that is closer to the average requirement. If you served meals at a population-mean intake level, most people would necessarily overconsume, and accumulated nutrients can act like toxins. So the data say the ketogenic diet meets or exceeds most nutrient requirements, including calcium."

Zoe "Doctor, I always thought calcium builds strong bones, so the more the better—isn't too much of a good thing still good?"

Dr. Lee "Important question. Calcium is indeed important for bones. It's also striking that blood calcium is 10,000-100,000 times more concentrated than intracellular calcium. So when calcium channels in the membrane open, calcium rushes in down its gradient and triggers intracellular signaling. In neurons, for example, when a presynaptic terminal fires, calcium influx causes vesicles loaded with neurotransmitter to fuse with the membrane and release their contents. But excess calcium can deposit in the optic nerve and increase the risk of cataracts. And of course, calcium overload contributing to kidney stones and renal strain is well established."

Zoe "So both nutrient deficiency and excess can cause problems."

Dr. Lee "Exactly. Now back to the study. This experimental ketogenic diet included avocado and nuts, but presumably not in large amounts. Adding legumes and increasing the proportion of nuts and seeds would likely improve the results further. Among seeds, perilla and sesame have up to 200 times more calcium than beef, and they are rich in minerals overall."

Susan "Wow—seeds are rich in lipids and have 200 times the calcium of beef? I should start eating them every day (laughs)."

Dr. Lee "There's one caveat. Sesame is high in omega-6, while perilla is high in omega-3. Try to consume at least two tablespoons of perilla a day. For a plant-based ketogenic diet, I recommend daily intake of legumes and seeds because of their mineral density."

Susan "Could you explain the difference between omega-3 and omega-6? ^^"

Dr. Lee "Omega-3 and omega-6 are essential fatty acids. In nutrition, essential means the body cannot synthesize them, so they must come from food. Omega-3 is anti-inflammatory; omega-6 is pro-inflammatory. They have many other functions—even regulating gene expression."

Susan "Then I should only eat anti-inflammatory perilla seeds."

Dr. Lee (laughs) "Inflammation isn't always bad. If your skin is cut and microbes invade, inflammation must be triggered to stop their spread. The problem is that modern people eat far too much omega-6 relative to omega-3. The recommended ratio is about 1:1 to 1:3. Yet modern diets run 1:15 to 1:20—an enormous excess of omega-6."

Grace "That's why inflammation is such a problem in the U.S. as well, particularly post-surgical infections that won't heal. In the States, flaxseed is recommended as a high-omega-3 food, but perilla seed is not only rich in omega-3 but also has a wonderful aroma—it should become quite popular."

"Feasibility and Efficacy Data from a Ketogenic Diet Intervention in Alzheimer's Disease" (Brandt et al., 2019)

Dr. Lee "Now the third study: "Feasibility and Efficacy Data from a Ketogenic Diet Intervention in Alzheimer's Disease" (Brandt et al., 2019). Ten participants followed a ketogenic diet for one month and then returned to a standard diet to track the changes. Cognitive function was measured using the Alzheimer's Disease Assessment Scale–cognitive subscale (ADAS-Cog). As Figure 6-6 shows, cognitive scores improved up to three months. After three months, when participants stopped the ketogenic diet, scores fell again—evidence that the cognitive gains over those three months were driven by the diet."

Grace "Doctor, I'm 82 now. I've been vegetarian since childhood, so I've always felt confident about my health. A few years ago I fractured a bone and went to the hospital, and they said my bone age was mid-thirties. But dementia has always been a worry. Hearing that not just plant-based eating but also a ketogenic diet helps prevent dementia gives me even more peace of mind."

Dr. Lee "Grace, I know you have lived a vegetarian life faithfully, grounded in your faith. A truly admirable life. I'm sure your health is closely tied to your plant-based eating."

Grace "Doctor, as you know, I once injured my head when I fell on a bus and had to undergo brain surgery, leaving my face swollen for a while. While I was studying nutrition in the U.S., I tried to get enough protein by making seitan and similar wheat-based mock meats. When you warned me that gluten can be harmful, I stopped eating wheat-based mock meats. On your recommendation I switched to soybeans and added more nuts. Following the ketogenic plan, my body became noticeably healthier and the swelling in my face disappeared. Honestly, much of what I had been taught in the U.S. turned out to be mistaken. I learned that I don't need to eat the high calorie amounts the textbooks prescribed—my health improved when I changed my diet."