The gut microbiome, which consists of the vast community of bacteria, fungi, viruses, and other microorganisms living in the digestive tract, plays a crucial role in overall health. It influences digestion, nutrient absorption, immune function, metabolism, and even aspects of mental well-being.
While the microbiome is constantly evolving throughout life, ageing can bring significant changes to the composition and diversity of gut microbes, potentially affecting health outcomes in midlife and beyond.
DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.
After the age of 45, many people begin to experience physiological changes linked to ageing, including shifts in hormone levels, metabolism, body composition, immune function, and digestive health. At the same time, lifestyle factors such as dietary habits, physical activity, stress, medication use, sleep patterns, and chronic health conditions may further influence the balance of microorganisms in the gut.
To understand this better, we spoke with an expert.
How the gut microbiome changes after 45
Kanikka Malhotra, consultant dietician and certified diabetes educator, tells indianexpress.com, “After 45, your gut undergoes measurable shifts: microbial diversity declines, beneficial bacteria like Faecalibacterium and Akkermansia diminish, while potentially harmful species increase.”
She adds that this matters because these organisms regulate nutrient absorption, produce short-chain fatty acids that fuel your colon, and train your immune system. “The result? Slower digestion, increased bloating, weaker immunity against infections, and altered metabolism make weight management harder. You may also notice changes in bowel regularity and energy levels. Your gut barrier becomes more permeable, allowing bacterial toxins to enter your bloodstream, a state called “leaky gut”, triggering low-grade inflammation linked to joint pain, brain fog, and metabolic slowdown. Understanding these shifts empowers proactive dietary choices.”
Ageing vs lifestyle: What drives microbiome changes?
So, roughly 30% of age-related microbiome change is inherent biological ageing, but 70 percent stems from modifiable lifestyle factors. Malhotra notes that diet is the strongest lever; processed foods, low fibre, and high sugar accelerate dysbiosis, while whole foods reverse it. Exercise increases beneficial bacteria diversity within weeks. Sleep deprivation and chronic stress suppress Lactobacillus and Bifidobacterium.
“Antibiotics reshape your microbial landscape for months. Chronic conditions like diabetes and inflammatory bowel disease also alter composition. But the encouraging news is that midlife is when small dietary and lifestyle corrections compound significantly, offering a genuine window to slow or even partially reverse unfavourable changes,” shares the expert.
Supporting gut health in midlife
Prioritise fibre, Malhotra says, aiming for 30 to 35 grams daily from vegetables, whole grains, legumes, and seeds, to feed beneficial bacteria that produce butyrate, your colon’s preferred fuel. Include fermented foods such as yoghurt, idli, dosa, or kimchi weekly for live cultures. Polyphenol-rich foods like berries, green tea, and turmeric modify bacterial metabolism favourably.
“Limit ultra-processed foods, which promote harmful species. Move daily; even 30 minutes of walking shifts microbial composition. Manage stress through meditation or yoga, since your gut-brain axis is bidirectional. Prioritise 7 to 8 hours of quality sleep. If antibiotics are necessary, discuss probiotic timing with your doctor. Consider prebiotic-rich foods like garlic, onion, and banana. These habits work synergistically; consistency matters more than perfection,” asserts Malhotra.
DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.
The gut microbiome evolves with age | Source: AI Generated 
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