Your body hosts trillions of bacteria, viruses, and fungi, collectively known as the microbiome. While some bacteria are linked to disease, many play essential roles in supporting your immune system, heart health, weight management, and overall well-being. This article delves into the significance of the gut microbiome and its impact on health.

What Is Gut Microbiome?

Interestingly, bacterial cells outnumber human cells in the body, with approximately 40 trillion bacterial cells compared to 30 trillion human cells. With up to 1,000 species of bacteria present in the gut, each plays a distinct role. While most bacteria contribute positively to health, some can be harmful. Together, these microbes weigh around 1–2 kilograms, functioning almost like an additional organ essential for overall well-being.

How Does Gut Microbiome Influence Your Health?

The relationship between humans and microbes has evolved over millions of years, with the gut microbiome playing a crucial role from birth. Initial exposure to microbes occurs during birth, and some evidence suggests that exposure begins in the womb. As the microbiome diversifies, it starts influencing key bodily functions:

Digestion of breast milk: Beneficial bacteria like Bifidobacteria help break down essential sugars in breast milk, supporting infant growth.

Fiber digestion: Some bacteria process fiber into short-chain fatty acids, which contribute to gut health and reduce risks of obesity, diabetes, and heart disease.

Immune system regulation: The gut microbiome interacts with immune cells, influencing how the body responds to infections.

Brain health: Emerging research suggests a link between the gut microbiome and brain function, potentially affecting mental health and neurological processes.

Gut Microbiome And Weight Management

An imbalance between beneficial and harmful microbes, known as gut dysbiosis, may contribute to weight gain. Studies on identical twins—one with obesity and the other without—suggest that microbiome composition plays a role in body weight independent of genetics. Additionally, animal studies indicate that gut bacteria can influence weight gain, even when calorie intake remains constant.

Probiotics, beneficial bacteria found in supplements and certain foods, can help restore gut balance and support weight loss, though their effects may be modest.

Gut Health And Disease Prevention

The gut microbiome plays a vital role in preventing and managing conditions like irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Imbalances in gut bacteria may lead to bloating, cramps, and digestive issues. On the other hand, beneficial bacteria like Bifidobacteria and Lactobacilli help strengthen the intestinal lining, reducing the risk of gut-related disorders.

Impact On Heart Health

Research suggests that the gut microbiome influences heart health by affecting cholesterol levels and blood pressure. Certain harmful bacteria produce trimethylamine N-oxide (TMAO), a compound linked to blocked arteries and heart disease. However, probiotics, particularly those containing Lactobacilli, may help reduce cholesterol levels and promote cardiovascular health.

Blood Sugar Regulation And Diabetes Risk

The gut microbiome also plays a role in regulating blood sugar levels. Research on infants genetically predisposed to type 1 diabetes indicates that gut microbiome diversity declines before disease onset. Furthermore, individual variations in gut bacteria may explain why people experience different blood sugar responses to the same foods.

Connection Between Gut And Brain

The gut is physically connected to the brain through nerves, and certain bacteria help produce neurotransmitters like serotonin, which influence mood and mental health. Studies indicate that people with mental health disorders often have different gut bacteria compared to those without such conditions. Additionally, some probiotics have shown promise in alleviating symptoms of depression and anxiety.

Tips For Healthier Gut Microbiome

Maintaining a balanced gut microbiome is crucial for overall health. Here are some strategies to support gut health:

• Eat a diverse range of foods: A varied diet rich in fiber, legumes, and fruits promotes microbial diversity.
• Consume fermented foods: Yogurt, kefir, and sauerkraut contain probiotics that enhance gut health.
• Limit artificial sweeteners: Some artificial sweeteners can encourage the growth of harmful bacteria.
• Include prebiotic foods: Bananas, oats, and asparagus contain fibers that nourish beneficial bacteria.
• Breastfeed infants when possible: Breastfeeding promotes a healthier gut microbiome in babies.
• Choose whole grains: Whole grains contain fiber and beneficial compounds that support digestive health.
• Opt for a plant-based diet: Vegetarian diets may reduce inflammation and support a healthier gut microbiome.
• Consume polyphenol-rich foods: Green tea, dark chocolate, and olive oil contain compounds that foster beneficial bacteria.
• Take probiotics if needed: Probiotic supplements can help restore gut balance after disruptions, such as antibiotic use.
• Use antibiotics cautiously: While antibiotics can be life-saving, overuse can harm beneficial gut bacteria.

The NHS is urging millions of people across the UK to take vitamin D to support overall health, but experts say certain symptoms should not be ignored. In a post shared on X, an NHS spokesperson said: “From October to March we can’t make enough vitamin D from sunlight, so to keep bones and muscles healthy, it’s best to take a daily 10 microgram supplement of vitamin D. You can get vitamin D from most pharmacies and retailers.”

While health professionals agree that vitamin D supplementation is important for many people, especially during the colder months, they stress that it should be taken carefully.

Why Does Sunlight Matter For Vitamin D Production?

Sunlight plays a crucial role in how the body makes vitamin D. UVB rays trigger a reaction in the skin that converts a compound called 7-dehydrocholesterol into vitamin D3. This form of vitamin D is essential for absorbing calcium, maintaining strong bones, and supporting the immune system.

As sunlight in the UK is not strong enough between autumn and early spring, the government advises everyone to consider taking a daily supplement of 10 micrograms, or 400 IU. Relying on food alone is often not enough to meet daily needs during this period.

Expert Warns Too Much Vitamin D Can Backfire

Biomedical scientist Tobias Mapulanga, who co-founded Repose Healthcare, has warned that some people may be taking more vitamin D than their bodies can handle. He explained that as winter advice circulates, many people add tablets, sprays, or gummies without realising they are doubling up.

He said that symptoms such as constant thirst, needing the toilet more often, nausea, stomach discomfort or constipation, headaches, mental fog, and new aches or cramps can appear soon after increasing vitamin D intake. These signs are often mistaken for winter illnesses, when they may actually point to excess supplementation.

“The message is simple,” he added. “The right dose helps, but taking too much can leave you feeling worse, not better.”

High-Dose Supplements Raise Safety Concerns

Research shows that 42% of UK adults reported taking vitamin D supplements in the past year. However, an investigation by Which? found some vitamin D products on sale contained doses as high as 12.5 times the recommended safe upper limit.

NHS England also logged 42 incidents over a two-year period where high-strength vitamin D was given more often than intended. Some of these cases led to hospital treatment for hypercalcaemia, a condition caused by too much calcium in the blood, according to reports from Bristol Live.

Stop Taking Vitamin D If You Notice These Warning Signs

1. Ongoing thirst and frequent trips to the toilet

If you suddenly feel unusually thirsty or find yourself urinating more often after starting vitamin D, it may be a sign you’re overdoing it. Cut back to a single 10 microgram tablet and stop using any additional vitamin D products if this happens.

Too much vitamin D can disrupt fluid and salt balance in the body, leaving you dehydrated and running to the bathroom. Check labels carefully and remove multivitamins, sprays, gummies, and fortified foods or drinks that also contain vitamin D.

Keep water close by and sip regularly while your body settles. Stay well below the upper limit of 100 micrograms, keep just one product visible, and put the rest out of sight to avoid accidental doubling.

2. Nausea, excessive burping, or stomach discomfort

Feeling sick, bloated, or dealing with an upset stomach after taking vitamin D suggests it isn’t agreeing with you. Try taking your supplement with a full meal and switch from sprays or gummies to a plain D3 tablet if symptoms persist.

Food helps protect the stomach lining, while sprays and gummies often contain sweeteners or flavourings that can irritate digestion. Choose a simple cholecalciferol tablet with minimal ingredients and reduce the dose to 10 micrograms.

Avoid fortified shakes or energy drinks until your stomach feels normal again.

3. New muscle cramps or bone aches

If you notice more aches in your bones or frequent muscle cramps after starting vitamin D, take it as a signal to reassess. Lower your dose and focus on staying well hydrated while eating mineral-rich foods.

Excess vitamin D can interfere with mineral balance, which muscles rely on, and dehydration can make cramping worse. Drink water with meals and include yoghurt, leafy greens, beans, and bananas in your diet.

Gentle stretching and short walks can ease stiffness. Stick to one 10 microgram supplement and avoid adding anything else until symptoms improve.

4. Brain fog or headaches

Trouble concentrating or recurring headaches can be signs that your vitamin D intake is too high. Replace multivitamins or high-strength products with a single 10 microgram D3 tablet.

High doses can raise calcium levels, and extra additives found in combined supplements may affect clarity of thought. Choose a product that contains only cholecalciferol and basic fillers.

Take it with food at the same time each day for consistency and better digestion. Avoid combined vitamin A and D products and focus on one simple supplement.

To prevent accidental overuse, review everything you take that contains vitamin D. Spread out all tablets, sprays, gummies, and fortified foods, and read each label carefully. Convert IU to micrograms by dividing by 40 to make totals easier to track.

Discard any extras and stick to one daily 10 microgram source. Keep a note of symptoms such as thirst, frequent urination, stomach upset, cramps, or mental fog to see how they relate to your intake.

For decades, iodine deficiency was a serious public health concern in India. Conditions like goitre and other iodine-related disorders were widespread until the nationwide introduction of iodised salt changed the picture. The move is widely seen as a major health success, preventing thyroid problems on a large scale.

Due to this, iodine has come to be almost inseparable from conversations around thyroid health. While its role is vital, doctors now caution that focusing on iodine alone can give a false sense of security.

“The thyroid is often misunderstood as a simple gland that switches on with iodine,” says Dr. Narendra BS, Lead Consultant – Endocrinology and Diabetology at Aster Whitefield. “In reality, it is a complex hormone-producing system that depends on several nutrients and physiological processes working together.”

Thyroid Does Not Run On Iodine Alone

The thyroid gland produces hormones that regulate metabolism, energy levels, body temperature, and even mood. Iodine is required to make these hormones, but it is only one step in a longer chain.

According to Dr. Narendra, problems can still arise even when iodine intake is adequate. “Hormone production and activation involve multiple stages. If other nutrients are lacking or the body is under stress, thyroid function can suffer despite normal iodine consumption,” he explains.

Nutrients That Quietly Support Thyroid Function

Several nutrients play supporting roles in keeping the thyroid healthy. Selenium is needed to activate thyroid hormones into their usable form. Iron is essential for hormone production itself, which is why thyroid disorders and anaemia often occur together. Zinc contributes to hormone synthesis, while adequate protein levels help transport thyroid hormones through the bloodstream.

“When these nutrients are missing, patients may continue to experience symptoms even though they are using iodised salt regularly,” Dr. Narendra notes.

Diet Patterns Matter More

Modern eating habits can also place strain on the thyroid. Very restrictive diets, frequent meal skipping, or cutting out entire food groups can disrupt hormonal balance. Diets heavy in ultra-processed foods may increase inflammation and worsen overall metabolic health, indirectly affecting thyroid function.

“A varied, balanced diet supports not just the thyroid, but the entire endocrine system,” says Dr. Narendra. “Nutrition should be looked at as a whole, not reduced to a single nutrient.”

Lifestyle factors often overlooked in thyroid care include stress and sleep. Chronic stress and poor sleep quality can interfere with how thyroid hormones are converted and used in the body.

“This is why some people feel unwell despite having ‘normal’ thyroid blood test results,” Dr. Narendra explains. “Stress hormones can mask or worsen symptoms, making the problem harder to identify if we focus only on iodine levels.”

When Salt Alone Is Not The Solution

Many people turn to iodised salt hoping it will ease fatigue, weight gain, or hair loss. While correcting iodine deficiency is important, these symptoms are frequently linked to broader thyroid disorders, including autoimmune conditions, which require medical evaluation and proper treatment.

“Iodised salt prevents iodine deficiency, but it cannot correct poor diet, chronic stress, sleep deprivation, or undiagnosed thyroid disease,” Dr. Narendra cautions.

Iodised salt is a starting point, not a complete solution. It plays a crucial role in preventing iodine deficiency, but true thyroid health depends on balanced nutrition, healthy habits, and timely medical care. The thyroid needs more than what comes from the saltshaker to function well.

A pharmacist has warned that people taking certain long-term medications should stay alert to subtle symptoms such as numbness, tingling, and an unusually red or sore tongue. According to Superdrug Pharmacy Superintendent Niamh McMillan, as per Mirror, the signs are often easy to dismiss and may quietly develop over time in people with low vitamin B12 levels.

Pharmacist Warns Certain Medicines May Trigger Overlooked Vitamin B12 Symptoms

McMillan explained that vitamin B12 plays a vital role in keeping nerves and blood cells healthy. A shortage can build up slowly, which means early symptoms are often brushed aside or mistaken for everyday fatigue.

She said common warning signs include persistent tiredness or weakness, breathlessness, headaches, dizziness, pale skin, and a sore or red tongue. Some people may also notice pins and needles or numbness in their hands or feet, memory lapses, trouble focusing, or changes in mood such as feeling low or unusually irritable.

Who Is Most At Risk Of Low B12 Levels?

Vitamin B12 deficiency occurs when the body either does not get enough of the vitamin from food or struggles to absorb it properly. McMillan noted that people following vegetarian or vegan diets are at higher risk, as B12 is naturally found mainly in animal products.

Older adults are also more vulnerable, as are people with digestive conditions such as coeliac disease or Crohn’s disease. In addition, those taking certain medications may be affected, particularly long-term acid-reducing drugs such as proton pump inhibitors or diabetes medication like metformin.

Dietary Sources That Help Maintain B12 Levels

To reduce the risk of deficiency, McMillan advised including reliable dietary sources of vitamin B12 wherever possible. Foods naturally rich in the vitamin include meat, fish, eggs, milk, cheese, and yoghurt.

For people who avoid animal products, fortified foods such as some breakfast cereals and plant-based milks can help support intake. In some cases, supplements may also be useful, especially when diet alone is not enough or absorption is impaired.

When To Seek Medical Advice?

McMillan stressed that anyone experiencing symptoms or falling into a higher-risk group should speak to a healthcare professional. A simple blood test can measure B12 levels, and early treatment can help prevent lasting nerve damage or other complications.

She added that Superdrug Health Clinics offer a Vitamin B12 Injection Service at selected UK locations, following clinical assessment or confirmation of deficiency.

How Medications Can Interfere With Vitamin B12?

Several commonly prescribed medications can affect how the body absorbs or uses vitamin B12. This often happens because the drugs alter conditions in the stomach or gut, making it harder for B12 to be released from food or absorbed into the bloodstream.

Medications Linked to Vitamin B12 Deficiency

The most frequently associated medications include:

• Proton Pump Inhibitors (PPIs): such as omeprazole, esomeprazole, and lansoprazole
• H2 Blockers: including famotidine and cimetidine
• Metformin
• Oral contraceptives, although experts continue to debate whether these cause a true deficiency
• Colchicine, used to treat gout and known to damage the intestinal lining
• Anticonvulsants, including drugs like phenytoin and phenobarbital, which can affect B-vitamin metabolism
• Nitrous oxide, commonly known as laughing gas, which can rapidly inactivate existing B12 in the body
• Antibiotics, particularly long-term use of chloramphenicol or neomycin, which can disrupt gut bacteria involved in B12 processing

What To Do If You Take These Medications Long Term?

Experts advise people on these medicines not to stop treatment without medical guidance. Instead, they recommend staying alert for symptoms such as fatigue, tingling or numbness in the hands or feet, brain fog, or a sore, red tongue.

Getting tested is also key. A straightforward blood test can confirm B12 levels, and many doctors now suggest regular screening for patients who take metformin or proton pump inhibitors over extended periods.