Psyllium

Psyllium is the only fibre supplement with FDA-approved health claims for both cholesterol lowering and blood glucose reduction. That regulatory bar is high, and psyllium cleared it because the evidence is unusually consistent: it works, it works reliably, and the mechanism is well understood.

Why It Matters for Longevity

The longevity case for psyllium rests on three pillars: cholesterol, blood sugar, and gut health.

For cholesterol, psyllium's soluble fibre forms a viscous gel in the small intestine that physically traps bile acids, preventing their reabsorption. Your liver then pulls LDL cholesterol from the blood to make replacement bile acids. A meta-analysis of 21 RCTs (Wei et al., 2009, PMID 19368716) confirmed LDL reductions of about 7% -- and the book places psyllium within a broader "cholesterol-lowering food portfolio" (alongside oats, legumes, and plant sterols) that achieved a combined 13% LDL reduction in a Canadian trial. That portfolio approach rivals statin therapy for moderate-risk individuals.

For blood sugar, the same viscous gel slows glucose absorption after meals, flattening the postprandial spike. McRorie (2015, PMID 25972618) calls psyllium the gold standard for gel-forming fibre and notes that no other supplemental fibre has sufficient evidence for this dual health claim.

For gut health, the story gets personal. The book cites evidence that psyllium reduces the severity of colitis and improves gastrointestinal symptoms in ulcerative colitis patients in remission. Jalanka et al. (2019, PMID 30669509) showed that psyllium supplementation increased Faecalibacterium abundance -- a butyrate-producing genus that maintains the gut barrier and suppresses inflammation. Butyrate is the primary fuel for colonocytes, and its depletion is a hallmark of inflammatory bowel disease.

How to Use It

Take 5-10g of psyllium husk daily, mixed into at least 250ml of water or another liquid. This is non-negotiable: without adequate water, psyllium can cause intestinal obstruction. Start with a lower dose and increase gradually to avoid bloating. Mix into smoothies, stir into oat porridge, or blend with yogurt. Timing matters less than consistency -- take it at whatever point in your day you will actually remember. Some people prefer it 30 minutes before meals to blunt glucose spikes; others add it to breakfast.

What to Pair It With

Flavor Profile

Psyllium is essentially flavourless -- slightly earthy, slightly hay-like, and entirely unremarkable. This is its greatest culinary advantage: it disappears into almost anything. The texture when hydrated is mucilaginous, which some people find off-putting in plain water but barely notice in a smoothie or porridge.

The Science

• Wei et al. (2009): Meta-analysis of 21 RCTs confirming 7% LDL reduction (PMID 19368716)
• McRorie (2015): Psyllium is the only fibre with FDA-approved claims for cholesterol and glucose (PMID 25972618)
• Jalanka et al. (2019): Psyllium increases butyrate-producing Faecalibacterium in healthy adults (PMID 30669509)
• Examine.com: Strong evidence for cholesterol, glucose, and bowel regularity benefits

Key Nutrients