Hypertension

High blood pressure is one of the most common chronic conditions in the UK, however, due to the lack of warning symptoms, many people don't know they have it. It can take years, sometimes decades, before the damage it causes becomes visible, by which point, the risk of stroke, heart attack, or kidney disease is already elevated.

High blood pressure, or hypertension, affects around 14 million adults in England, roughly one in three (3). It contributes to approximately 75,000 deaths per year and accounts for 12% of all visits to primary care, costing the NHS up to £2.1 billion annually (3). Despite this, around one in three people with hypertension in England remain undiagnosed, and among younger adults, the proportion who are unaware they have the condition is even higher (4).

This article takes an evidence-informed look at what hypertension is, why it develops, and what the research says about the lifestyle and dietary changes most likely to make a difference: whether you have a diagnosis, suspect you might, or simply want to protect your cardiovascular health long-term. 

Blood Pressure Readings

When a blood pressure reading is taken, two numbers are recorded, for example, 128/82 mmHg. These reflect two distinct phases of the cardiac cycle. The upper figure, systolic pressure, measures the force of blood against artery walls as the heart contracts and pumps blood out into circulation. The lower figure, diastolic pressure, captures the pressure when the heart is between beats, relaxing and refilling. 

Readings between 130/80 and 139/89 mmHg are increasingly recognised as 'high normal' or stage 1 hypertension, particularly in people with other cardiovascular risk factors. “Hypertension” is defined using thresholds established by NICE guidelines, in which a clinic reading of 140/90 mmHg or above, confirmed by ambulatory or home monitoring, is used to diagnose the condition in most adults (3).

A single elevated reading is not necessarily cause for alarm. But years of consistently high pressure gradually damage artery walls, making them stiffer and less elastic, promoting the build-up of fatty deposits, and increasing the workload placed on the heart. Over time, this raises the risk of stroke, heart attack, heart failure, chronic kidney disease, and cognitive decline (3).

The Root Causes of High Blood Pressure

In most cases, there is no single identifiable cause for hypertension. This is referred to as primary or essential hypertension, and it reflects the cumulative effect of genetic predisposition interacting with long-term lifestyle and environmental factors (3). A smaller proportion of cases are secondary to an underlying condition, such as kidney disease, hormonal disorders, or certain medications.

Diets high in sodium and ultra-processed foods directly raise blood pressure through their effects on fluid retention and vascular tone, one of the most well-established lifestyle contributors to primary hypertension. Low intake of potassium, which is abundant in fruits, vegetables, legumes, and wholegrains, compounds this effect, since potassium and sodium work in opposition in the body (1).

Excess weight, particularly around the abdomen, adds a further layer of strain. It forces the heart to work harder and puts the body's blood pressure regulation system under pressure. Over time, blood vessel walls gradually lose their ability to relax and widen properly, meaning the heart has to push against greater resistance with every beat.

Hypertension rarely exists in isolation. It frequently co-occurs with elevated blood glucose, elevated cholesterol, and excess weight, conditions that share common root causes and are a central focus of this series. To a meaningful degree, they can be addressed together through the same lifestyle changes.

How Does Diet Affect Blood Pressure?

To understand why specific foods and dietary patterns have such a measurable effect on blood pressure, it helps to look at the biological mechanisms involved. There are four key pathways, which tend to reinforce each other over time.

1. Potassium and sodium balance. The kidneys regulate blood pressure partly through their management of sodium and fluid. Potassium, found in high concentrations in leafy greens, legumes, bananas, sweet potatoes, and most whole plant foods, directly counteracts the blood-pressure-raising effects of sodium by promoting its excretion and helping blood vessels relax (1). Most people in the UK consume far more sodium and far less potassium than is optimal.

2. How well your blood vessels can relax. Whole plant foods, particularly those rich in dietary nitrates (beetroot, leafy greens), polyphenols (berries, dark chocolate, olive oil), and vitamin C, support the ability of blood vessel walls to produce nitric oxide, the molecule responsible for allowing blood vessels to widen and relax (5). The better your blood vessels can do this, the less resistance your heart has to pump against, and the lower your blood pressure tends to be.

3. Fibre and gut signalling. Higher dietary fibre is consistently associated with improved cardiovascular health, partly through its effects on body weight and blood glucose, and partly through direct effects on gut-derived signalling molecules that influence how blood vessels behave (5).

4. Body composition. Excess fat, particularly visceral fat stored around the abdomen, forces the heart to work harder, drives inflammation, and disrupts the hormonal signals that help regulate blood pressure (3). Diets built around whole, minimally processed foods tend to support a healthier body composition over time, not by restriction, but by naturally crowding out the calorie-dense, nutrient-poor foods most strongly linked to fat accumulation. Even modest reductions in abdominal fat produce measurable blood pressure improvements in most people.

Could Lifestyle Changes Lower Your Blood Pressure?

The short answer is, yes. The most extensively studied dietary intervention for blood pressure is the DASH (Dietary Approaches to Stop Hypertension) diet, first tested in a landmark clinical trial that demonstrated significant reductions in blood pressure within weeks of adopting a diet rich in fruits, vegetables, low-fat dairy products, and wholegrains, with reduced saturated fat and sodium (1). The effects were observed across a broad population, including people with and without diagnosed hypertension.

Building on this foundation, more recent evidence has specifically examined plant-based dietary patterns. A 2023 systematic review in Current Hypertension Reports, covering intervention studies from 2020 onwards, concluded that the overwhelming majority of trials demonstrate lower blood pressure in people following plant-based diets compared to those eating diets based on animal products (5). A meta-analysis of 15 randomised controlled trials found that vegetarian diets reduced systolic blood pressure by approximately 2.66 mmHg and diastolic by approximately 1.69 mmHg compared to omnivorous diets, with the greatest reductions seen in those following fully plant-based or vegan diets (5, 6).

Research from Warwick Medical School, published in the Journal of Hypertension, offers a particularly encouraging finding for those who are not ready or willing to adopt a fully plant-based diet: any meaningful shift toward plant foods, even in diets that still include some animal products, appears to confer blood pressure benefits (2). The direction of change matters more than the destination.

For context, a sustained drop of 5 mmHg in systolic pressure, well within what dietary change can achieve, is roughly equivalent to the effect of a standard first-line blood pressure medication (3). For someone in the high-normal range, that kind of shift can mean the difference between a diagnosis and staying clear of one.

5 Steps To Lower Blood Pressure

The following are evidence-based actions with documented effects on blood pressure, relevant whether you have a diagnosis, are in the 'high normal' range, or simply want to protect your cardiovascular health long-term (3, 5). None requires perfection, and all can be introduced gradually.

1. Build meals around whole foods and reduce ultra-processed ready meals. Vegetables, legumes, wholegrains, fruits, nuts, and seeds provide the potassium, fibre, and vascular-protective compounds most closely associated with lower blood pressure. Swapping boxed cereal for porridge, bottled sauces for simple olive oil and herbs, or a ready meal for a quick lentil dish are small changes that add up quickly (3). Most dietary salt we consume in modern days is hidden inside the bread, sauces, and ready meals most of us eat daily, which makes it hard to control. 

2. Move regularly. Thirty minutes of brisk walking most days is enough to produce meaningful blood pressure reductions. Research shows aerobic exercise can lower systolic pressure by 5 to 8 mmHg in people with hypertension (3). It doesn't need to be intense or structured, a walk at lunch, cycling to the shops, or a swim twice a week all count. The key is consistency over intensity.

3. Prioritise sleep. Aim for seven to nine hours. Consistently sleeping fewer than six hours raises blood pressure through hormonal pathways that are difficult to offset elsewhere, no amount of dietary improvement fully compensates for chronic poor sleep (3). If sleep quality is the issue rather than duration, reducing screen time before bed, keeping a consistent sleep schedule, and limiting caffeine after midday are practical starting points.

4. Manage alcohol intake. Alcohol raises blood pressure through several mechanisms: it activates the stress response system, disrupts sleep quality, and over time contributes to weight gain around the abdomen (3). The effect is dose-dependent, the more regularly and heavily alcohol is consumed, the greater the impact. For those who want to cut back, alternating alcoholic drinks with sparkling water or designating a few alcohol-free evenings per week are small shifts that add up without requiring a wholesale lifestyle change.

5. Address stress. Chronic stress keeps the body in a low-level state of alert that raises blood pressure over time. There is no single solution, but small daily habits matter: brief walks, regular breaks from screens, and protecting time for rest are all supported by evidence. For those dealing with significant or persistent stress, speaking to a GP or mental health professional is worth considering.

Hypertension is common, serious, and for a meaningful proportion of people, substantially preventable and modifiable through diet and lifestyle. The evidence is consistent and growing: small, sustained changes to how we eat, move, sleep, and manage stress can shift blood pressure in a meaningful direction, and in doing so, reduce the risk of the cardiovascular events that hypertension leads to. Prevention is not about perfection. It is about building patterns that support the body over time.

If you are looking for support in translating this evidence into your own daily life, whether you want to understand your numbers, reduce your risk, or build a more sustainable approach to your health, I work with people individually and in small groups. Feel free to get in touch.

If you are currently taking medication for blood pressure, do not adjust or stop it without speaking to your GP or prescribing clinician first, including if you begin making dietary or lifestyle changes. As these factors improve, your blood pressure may fall, and your medication may need to be reviewed.

This article is part of a monthly series on Metabolic Health, which explores the conditions most closely linked to high blood pressure, elevated cholesterol, blood sugar dysregulation, and the role of body composition.

The next post explores Cholesterol: what the numbers mean, how diet influences them, and what the evidence says about reducing cardiovascular risk.