5 Key Nutrients That Bridge the Gap Between Gut Health and Heart Health

For years, cardiology and gastroenterology were treated as separate domains. But the science of the gut–heart axis tells a different story: your microbes are shaping your cardiovascular risk every day. Nutrients don’t just fuel the body; they modulate the microbiome, regulate inflammation, and influence whether arteries stay resilient or fragile.

I’ve seen again and again that when patients focus on the right nutrients, both their digestion and their cardiovascular profile begin to shift. Let’s look at five key players backed by evidence.

Table of Contents:

1. Dietary Fibre: The Foundation for SCFA Production

2. Omega-3 Fatty Acids: Anti-Inflammatory and Microbiome-Friendly

3. Polyphenols: The Antioxidant–Microbial Synergy

4. Choline and Carnitine: The Double-Edged Sword

5. Resistant Starch: Timing, Metabolism, and Microbial Rhythm

6. Clinical Insights

7. How I bring this into practice

1. Dietary Fibre: The Foundation for SCFA Production

Fibre isn’t just about regularity. When microbes ferment soluble fibres, they produce short-chain fatty acids (SCFAs) like acetate, propionate, and butyrate. These metabolites:

• Improve gut barrier integrity, preventing leakage of lipopolysaccharides (LPS) into circulation.

• Reduce systemic inflammation and protect endothelial function.

• Support lipid metabolism, lowering cholesterol and triglyceride levels (Marzullo P. et al., 2020; Rahman M. et al., 2022).

Clinically, I encourage aiming for a diverse fibre intake, including vegetables, legumes, and resistant starches, because different fibres feed different microbes. Diversity is protection.

2. Omega-3 Fatty Acids: Anti-Inflammatory and Microbiome-Friendly

Omega-3s, especially EPA and DHA, play a dual role: they directly reduce vascular inflammation and they shape microbial ecology. Evidence shows omega-3s enrich bacteria that produce SCFAs and suppress those that contribute to TMAO (a metabolite linked to atherosclerosis) (Rahman M. et al., 2022; Sanz Y. et al., 2025). For patients, this means prioritising fatty fish or algal oils while also balancing omega-6 intake.

From a gut–heart perspective, omega-3s are a bridge nutrient. They work systemically and microbially at the same time. Recent reviews also highlight that higher omega-3 status improves endothelial function and stabilises arterial plaques, while supporting microbial diversity that protects against obesity-linked inflammation (Marzullo P. et al., 2020; Rahman M. et al., 2022; Sanz Y. et al., 2025). This makes omega-3s one of the few nutrients with direct evidence of benefit on both cardiovascular outcomes and gut ecology.

3. Polyphenols: The Antioxidant–Microbial Synergy

Polyphenols from foods like berries, green tea, cocoa, and olive oil don’t act alone. Many of their benefits are mediated through the gut microbiota. Once metabolised by microbes, polyphenols increase SCFA production, reduce oxidative stress, and modulate vascular tone (Sanz Y. et al., 2025).

In cardiometabolic care, I see polyphenols as a way to simultaneously nourish beneficial bacteria and directly dampen oxidative injury to vessels. They’re not just antioxidants; they’re microbiome modulators. Beyond this, studies link higher polyphenol intake to improved endothelial function and lower blood pressure, partly explained by shifts in microbial composition that reduce TMAO levels (Martins D. et al., 2024; Rahman M. et al., 2022). Polyphenols also enhance microbial diversity and resilience, supporting long-term vascular protection and lowering the risk of atherosclerosis (Sanz Y. et al., 2025).

4. Choline and Carnitine: The Double-Edged Sword

These nutrients, abundant in red meat, eggs, and dairy, illustrate the darker side of the gut–heart connection. Gut microbes metabolise them into trimethylamine (TMA), which is converted in the liver to TMAO. Elevated TMAO is consistently associated with a higher risk of cardiovascular events (Martins D. et al., 2024; Rahman M. et al., 2022).

This doesn’t mean patients need to avoid all choline. It’s essential for cell membranes and brain function. But it does highlight the importance of microbial balance. When dysbiosis dominates, even normal choline intake can become problematic. Clinically, this means moderating animal protein while supporting gut diversity through fibre and polyphenols. What’s emerging from recent analyses is that the impact of choline and carnitine depends less on the absolute intake and more on the microbial ecosystem they enter. A healthy microbiome tends to limit TMAO accumulation, while dysbiosis amplifies it (Sanz Y. et al., 2025). 

This opens the door to interventions such as probiotics, prebiotics, and plant-forward diets that buffer the negative cardiovascular effects without compromising choline’s essential roles (Marzullo P. et al., 2020; Rahman M. et al., 2022).

5. Resistant Starch: Timing, Metabolism, and Microbial Rhythm

Resistant starch, found in legumes, cooked and cooled potatoes, and green bananas, has a unique ability to regulate circadian aspects of metabolism. By slowing glucose absorption and enhancing butyrate production, it supports both glycaemic control and vascular health (Marzullo P. et al., 2020; Sanz Y. et al., 2025).

I often think of resistant starch as a “timing nutrient.” It smooths out post-meal spikes, aligns microbial fermentation with host metabolism, and provides sustained fuel for colonocytes. In cardiometabolic practice, it’s one of the simplest yet most overlooked tools. Emerging data also suggest that resistant starch may enhance metabolic flexibility, helping the body switch more efficiently between glucose and fat as fuel (Sanz Y. et al., 2025).

Clinical Insights

What ties these nutrients together is their impact on microbial metabolites. When fibre, omega-3s, polyphenols, and resistant starch dominate the diet, the microbiome generates anti-inflammatory SCFAs. When choline and carnitine dominate under dysbiosis, the output shifts toward pro-atherogenic TMAO.

The gut becomes a biochemical switchboard. And nutrition is how we program it.

How I bring this into practice

When I sit with patients, I don’t just look at cholesterol or blood pressure. I often run advanced lipids, hs-CRP, plasma TMAO where available, and stool testing for diversity and SCFA potential, because these markers tell me how the gut and heart are actually talking to each other (Marzullo P. et al., 2020; Martins D. et al., 2024).

On the nutrition side, I focus on structured increases in fibre (≥30 g/day) to drive SCFA production, targeted omega-3 intake (2–4 g EPA+DHA) for anti-inflammatory and plaque-stabilising effects, and polyphenol-rich foods to strengthen the gut–vascular axis (Martins D. et al., 2024; Sanz Y. et al., 2025).

For gut support, I often recommend prebiotic blends and probiotics with SCFA-producing strains, while encouraging moderation of red meat and processed foods to lower TMAO burden (Sanz Y. et al., 2025).

And finally, lifestyle is just as important. I ask patients to align meals with their circadian rhythm, since microbial metabolism is also clock-regulated, a simple step that can amplify both gut and cardiovascular health (Marzullo P. et al., 2020; Sanz Y. et al., 2025).

Conclusion

Gut and heart health are deeply connected through shared microbial and metabolic pathways. Focusing on key nutrients like fibre, omega-3s, and polyphenols creates small shifts that add up to long-term protection. If this resonates, share it with a colleague or patient who would benefit.

References:

1. Marzullo P., Di Renzo L., Pugliese G., De Siena M., Barrea L., Muscogiuri G., Colao A., Savastano S. (2020). From obesity through gut microbiota to cardiovascular diseases: a dangerous journey. International Journal of Obesity Supplements. doi: 10.1038/s41367-020-0017-1

2. Martins D., Silva C., Carlos Ferreira A., Dourado S., Albuquerque A., Saraiva F., Beatriz Batista A., Castro P., Leite-Moreira A., Barros A., Miranda I. (2024). Unravelling the Gut Microbiome Role in Cardiovascular Disease: A Systematic Review and a Meta-Analysis. MDPI. Biomolecules. https://doi.org/10.3390/biom14060731

3. Rahman M., Islam F., Or-Rashid H., Al Mamun A., Rahaman S., Islam M., Farzana Khan Meem A., Rani Sutradhar P., Mitra S., Ara Mimi A., Bin Emran T., Fatimawali., Idroes R., Ekawati Tallei T., Ahmed M., Cavalu S. (2022). The Gut Microbiota (Microbiome) in Cardiovascular Disease and Its Therapeutic Regulation. Frontiers in Cellular and Infection Microbiology. https://doi.org/10.3389/fcimb.2022.903570

4. Sanz Y., Cryan J., Deschasaux-Tanguy M., Elinav E., Lambrecht R., Veiga P. (2025). The gut microbiome connects nutrition and human health. Nature. https://doi.org/10.1038/s41575-025-01077-5