How Vitamin C serves to fight cancer cells

How Vitamin C works: 

Chemotherapy kills both cancer cells and white blood cells. White blood cells are the 'soldiers' in the body that uses H2O2 (Hydrogen Peroxide) as weapons to kill bad cells such as cancer cells, bad bacteria, or virus. 

These bad cells have iron in them, and they replicate by means of iron which is its food.
Abstaining from iron-rich food such as meat is necessary to keep these bad cells from replicating. 

Example:

Kim Hoon-ha, a Korean pharmacist Youtuber, made her father eat Ovo-Pescatarian diet (no meat, no dairy, but eggs and white fish allowed) and made his cancer disappear in 6 months. But as soon as he started eating meat once or twice a week for 3 months, as well as bread and coffee, the cancer grew 2 cm. https://www.youtube.com/shorts/H2MY9soJhys

But I think completely going vegan would be better, as Colin Campbell says even eggs and fish promotes cancer.

Her father was diagnosed with stage 4 non-small cell lung cancer (with metastases to the liver, lymph nodes, back of the head, and ribs). 

He initially underwent 6 cycles of chemotherapy (she mentions "Keytruda" — likely referring to pembrolizumab or a similar regimen in context, though she sometimes uses general terms).

Due to severe side effects from the chemo, they discontinued conventional anticancer treatment after those 6 cycles.

From that point onward, they switched to her integrative approach: strict diet changes, natural substances, supplements (Vitamin D, etc - ask Grok for details), and lifestyle modifications (what she calls her "five principles"). 

She claims the cancer became undetectable ("completely gone" in about 6 months) through this method, without further chemo, radiation, or surgery.

Kim Hoon-ha’s Foods/Drinks to Avoid + Brief Reasons

1. Kim Hoon-ha’s 8 Foods/Drinks to Avoid + Brief Reasons

   1. Red meat & processed meat
      Contains heme iron that feeds cancer cells and promotes metastasis.
   2. Milk & all dairy products
      Raises IGF-1 levels, which stimulates cancer cell growth.
   3. Cheese
      Concentrated dairy high in hormones and growth factors.
   4. Sugar & sweets
      Directly feeds cancer cells by raising blood sugar quickly.
   5. White rice
      Causes rapid blood sugar spikes that cancer cells love.
   6. Wheat flour products (white or whole wheat bread, noodles, pastries, etc.)
      Causes blood sugar spikes and potential inflammation. (She recommends other grains like brown rice, millet, sorghum) (She really does forbid even whole wheat. Barley is better but should be in moderation). 
   7. Cooking oils (all edible oils)
      Creates inflammation and oxidized fats when heated.
   8. Fried foods
      Combines bad oils with high heat, producing harmful compounds.
   9. Coffee
      Overstimulates the nervous system, increases stress hormones, and disrupts the body’s healing state.

   Details on why wheat is forbidden: 

Poor digestion and residue buildup
Wheat flour is hard to digest completely. Undigested particles remain in the gut and create “residue” that blocks smooth blood circulation. Poor circulation → the body becomes cooler.

Inflammation and circulatory slowdown
Wheat triggers low-grade inflammation in many people. This inflammation and the resulting sluggish blood flow make the extremities (hands and feet) cold and lower overall body temperature.

Blood sugar and energy effect
Even whole wheat causes relatively fast blood sugar changes. She believes this unstable energy metabolism contributes to a “cold” internal environment, unlike the more stable warmth from warm-cooked brown rice or mixed grains.

Personal observation
In her videos and books, she often says wheat-based foods (bread, noodles, etc.) make the body feel heavier, more tired, and colder — especially during cancer treatment when immunity and circulation are already weak.

Kim Hoon-ha’s  anti-cancer Juice– 7 Ingredients & Reasons

1. Apple
   Rich in pectin that helps produce anti-cancer substances in the intestines. Supports digestion and detoxification.
2. Carrot
   High in beta-carotene and antioxidants. Strengthens the immune system, especially important during chemotherapy.
3. Cabbage
   Contains glucosinolates that inhibit cancer cell growth. Strong anti-inflammatory effect and improves digestion.
4. Broccoli
   High in sulforaphane and vitamin C. Suppresses cancer cell growth and supports bone health.
5. Bell Pepper (preferably red or yellow)
   Excellent source of vitamin C and beta-carotene. Helps with cancer prevention and immune support.
6. Beet (Beetroot)
   Powerful alkalizing effect. Helps prevent cancer recurrence and metastasis by reducing body acidity.
7. Tomato
   Rich in lycopene. Removes free radicals and helps keep cells healthy and youthful.

Dr. Kim steams all of the above except apple, carrot, tomato and blends them in a blender. But I think it is better to cook the carrot and tomato.

H2O2 kills cancer cells or pathogens by reacting with the iron in them, called the Fenton reaction. The H2O2 then breaks down into oxygen and water.

When you take Vitamin C, half of it is converted into H2O2 and the other half into oxalate. (Sufficient water needs to be taken with Vitamin C to dilute this oxalate). So it provides the much needed H2O2 the body needs to combat cancer cells when there is a shortage of white blood cells as a result of chemotherapy killing them.

Orally taken Vitamin C (tablets, capsule) may be good enough to prevent very tiny cancer from getting bigger, but are too weak in case of fighting an ongoing cancer. For that IVC (Intravenous Vitamin C) Therapy must be used. But even this is usually recommended not as a standalone, but as an addition to the standard chemoradiation therapy.

Orally taking Vitamin C also kills the biofilms of bad bacteria in your gut to improve the gut microbiome, which helps the immune system.

Homemade water-kefir could be used to replenish the gut biome killed by chemotherapy. (A typical milk kefir may be dangerous, since as a dairy product it contains the protein casein which promotes growth of cancer cells, especially when exceeding 10% of total calorie.)

Source on dairy promoting cancer: Colin Campbell, author the The China Study.

IVC therapy is being recognized even in mainstream institutions in recent years:

The University of Iowa (UI) has been a leading mainstream academic institution conducting rigorous clinical trials on high-dose intravenous vitamin C (IVC, or pharmacological ascorbate) as an adjunct to standard treatments like chemotherapy and radiation for certain cancers. These are not alternative or fringe efforts—they're funded by the National Cancer Institute (NCI) since 2018 (a $9.7 million grant supporting trials in pancreatic cancer, glioblastoma, and non-small cell lung cancer), run through the Holden Comprehensive Cancer Center, and published in peer-reviewed journals.Key recent results (with dates added for clarity): 

• Pancreatic cancer (metastatic/stage 4): A randomized phase 2 trial (published November 2024 in Redox Biology) showed that adding high-dose IVC (75 g infusions three times weekly) to standard chemotherapy (gemcitabine + nab-paclitaxel) doubled median overall survival from ~8 months (control group, aligning with historical data) to 16 months. Progression-free survival also nearly doubled (from ~3.9–4 months to ~6.2 months). The trial was stopped early due to strong ethical signals of benefit. Results were announced publicly around November 11–14, 2024, with coverage in outlets like UI's own news, Healio, and others extending into 2025.
• Glioblastoma (aggressive brain cancer): A phase 2 trial's results were published in early 2024 (in Clinical Cancer Research). Adding high-dose IVC to standard chemoradiation (temozolomide + radiation) extended median survival by about 5 months compared to historical/expected outcomes with standard care alone (e.g., prior phase 1 data from ~2019 showed ~18 months median OS vs. historical ~14–15 months). Earlier phase 1 safety/efficacy hints dated back to publications around 2017–2019.

These trials emphasize IVC as complementary (added to chemo/radiation) to potentially enhance efficacy, reduce toxicities, improve quality of life, and extend survival—not as a standalone replacement. UI researchers (e.g., Joseph Cullen for pancreatic, Bryan Allen for glioblastoma) highlight mechanisms like generating hydrogen peroxide selectively toxic to cancer cells. No serious added toxicities were noted, and it's described as safe, inexpensive, and well-tolerated.

This represents a shift in some mainstream oncology circles: while IVC isn't yet standard care or FDA-approved for cancer, these NCI-funded, randomized trials at a major U.S. university hospital provide credible evidence supporting its adjunctive use in hard-to-treat cancers. Ongoing or related trials (e.g., lung cancer nearing completion) continue this line of research.