Podcast Summary: "Should you aim for an alkaline lifestyle?"

What's That Rash? – ABC News
Date: November 18, 2025
Hosts: Norman Swan, Sam, Ting
Main Theme:
This episode examines the popularity and scientific validity of alkaline diets and lifestyles. The hosts respond to listener questions about whether modern diets are too acidic, the physiological basis for alkaline diets, and the health claims associated with such diets—especially in relation to cancer and chronic disease.

1. Introduction to Alkaline Diets

• Listener questions (Brett and Annie) prompt a discussion:
  • Are modern diets too acidic?
  • Should we be aiming to eat more ‘alkaline’ foods?
• Popular trends noted: Alkaline water, low-acid diets, and commercial products to “balance pH”.
• Funny opening exchange:
  • Ting jokes that Norman has a “Live Laugh Love” sticker, leading to:

    "I'm probably less basic than I used to be.... Cause I'm more acid."
    — Norman Swan [01:19]

2. pH, the Body, and Acid-Base Balance

[02:59 - 05:50]

• What is pH?

  • pH = measure of hydrogen ion concentration (acidic below 7, neutral at 7, alkaline above 7).
  • Litmus paper memories:

    “I think I even made my own litmus paper using red cabbage.”
    — Sam [03:29]

• How does the body control pH?

  • Blood pH is tightly regulated (7.35 – 7.45).
  • Extreme deviations are life-threatening—critical for oxygen transport and enzyme function.
  • Regulation mechanisms: via lungs (CO₂ removal raises pH) and kidneys (excrete or retain acid/alkali in urine).

• Quote:

  “Our bodies do not work well... in life-threatening situations when we're too alkaline or too acidic, particularly too acidic.”
  — Norman Swan [03:51]

3. The Origins of the Alkaline Diet Trend

[05:50 - 10:48]

• Historical context:

  • 19th-century interest in acids and bases led to early research on diet and body pH.
  • 1933: Study with ammonium chloride/phosphoric acid—body adjusted, except under extreme conditions (like diabetic acidosis).
  • Research used “acid-ash” and “alkaline-ash” (burning foods to ash, measuring pH post-metabolism).

    “[Citrus fruits] are acidic, but really it's about what's left over from those foods once your body's metabolized them.”
    — Sam [08:20]

• Early observations:

  • Meat-heavy (acidic) diets vs. plant-heavy (alkaline) diets
  • Short-term, extreme diets caused nausea (1930s study lasted "two and two-thirds of a day" before stopping).
  • 1960s: Vegetarians had more alkaline urine, but this was about the diet, not their blood pH.

4. What Alkaline Diets Really Do

[10:48 - 13:38]

• Correlation vs. Causation:

  • Alkaline diets are healthier not because they change your blood pH, but due to increased intake of fruits, vegetables, and fewer processed foods/meat.
  • The "Mediterranean diet" theme arises:

    “It was the Mediterranean diet.”
    — Norman Swan [10:31]

• Practical upshot:

  • “Alkaline diet” = high-fruit and veg, low-meat diet.
  • Consuming alkaline water or “alkaline products”? Not necessary or impactful.
  • Risks of acid diets?
    Slight evidence of increased calcium in urine (potential osteoporosis or kidney stone risk), but overall, calcium balance is tightly controlled in the body.

5. Acidosis, Chronic Disease, and Diet

[12:27 - 15:24]

• Serious acidosis: Only occurs with conditions like untreated type 1 diabetes; otherwise, body self-regulates.
• Is “low-grade metabolic acidosis” a chronic risk?
  • Not well established in research; possible, but hard to separate from the general harms of poor diets.
• Quote:

  "A simple solution being, just have more alkali in your life—one is that you think, well, I'll just drink alkaline water. That's not going to cut it...what's going to benefit you is more alkaline foods which happen to benefit you independent of their alkaline activity."
  — Norman Swan [13:57]

• Homeostasis: Body rigorously corrects disruptions to pH; diet cannot meaningfully change blood pH in healthy people.

6. Fad Diets, Claims, and the Cancer Controversy

[15:24 - 16:27]

• Cancer claim: Some say alkaline diets “fight cancer” by altering tumor environments.
  • Reality: Healthier diets may improve immunological resilience, but diet does not alter tumor pH directly.
  • Quote:

    “It probably does [help], but not because of being alkaline...it'll make the immune system more active, your microbiome more active, and in general you'll be healthier... but it won't influence necessarily the immediate PH environment around a tumour.”
    — Norman Swan [15:32]

7. Alkaline Diet vs. Low-Acid Diet: Is There a Difference?

[16:14 - 16:55]

• No meaningful difference; low-acid diet = alkaline diet in popular understanding.

8. Bottom Line & Health Guidance

[16:34 - 17:03]

• Best practice:
  • Don’t obsess about “alkaline” products.
  • Eat more fruits and vegetables, less meat, and limit processed foods.
• Quote:

  “If you like the idea of an alkaline diet, go for it. But don't assume that if you take an alkaline product such as alkaline water, that's going to cut it.”
  — Norman Swan [16:39] “Foods to eat: basically fruit and vegetables, less meat and avoiding ultra processed foods.”
  — Sam [16:55]

9. Notable Quotes & Memorable Moments

• Humorous banter and asides:
  • “Could that interfere with the results? …I don't know if eating a lot of red cabbage causes you to be alkaline or acidic.”
    — Ting [03:39]
  • “It’s an extreme keto diet, isn’t it?”
    — Norman Swan on meat-only study [09:29]
• On homeostasis and “simple solutions for complicated problems”:
  • “Simple solutions for complicated problems…are almost always wrong.”
    — Norman Swan [13:57]

10. Key Timestamps

• [01:06] – Show proper begins, listener questions introduced
• [02:59] – Explanation of pH and acid-base balance
• [05:50] – Origins and early research of acid and alkaline diets
• [08:20] – Acid-ash vs. alkaline-ash explanation
• [10:31] – Mediterranean/plant-heavy diet discussion
• [13:38] – Fad-diet critique, homeostasis, and marketing commentary
• [15:24] – Alkaline diet and cancer claims
• [16:55] – Bottom line and recommendations

Summary for New Listeners

In this approachable, witty discussion, the hosts debunk the myth that alkaline diets alter blood pH and deliver health benefits that way. Instead, the benefits arise from the core advice repeated by health authorities: eat more plants, avoid processed foods, and reduce meat intake. The body's acid-base balance is robustly self-regulated; you cannot shift it meaningfully by dietary tweaks. While eating well supports general health—and may indirectly support cancer resistance—it is not because of an "alkaline" effect. The allure of "simple solutions to complicated problems" can mislead, but following dietary guidelines will serve you best.