Garlic and Blood Pressure

Introduction

Did you know that garlic can help control your high blood pressure and can be as effective as blood pressure medication if taken every day? Garlic (Allium sativum) is a common bulb used in most cuisines all over the world, and knowledge of its health benefits can be traced back to the ancient Egyptian and Roman eras. Studies have shown the benefits of Kyolic-aged garlic extract, which can help to control your systolic and diastolic blood pressures, blood thickness and cholesterol levels.¹ 

Blood pressure measures the force that your heart uses to pump the blood in your body. It is measured in millimetres of mercury (mmHg), and it is expressed in 2 figures: systolic blood pressure, the top number, is the force that your heart creates on the blood vessels when pumping your blood out it, and diastolic pressure, the bottom number, is the resistance force against the vessels that your heart produces between beats. A normal blood pressure level is anywhere between 90/60 mm Hg and 120/80 mm Hg, while a high blood pressure level is considered when your readings are 140/90 mm Hg or above.² 

We know that a variety of factors affect our blood pressure, like stress, caffeine or alcohol, but what is the biological mechanism behind it? There are three main mechanisms to control the blood pressure in our body:⁴ 

Through sensors called baroreceptors: The stretching of a blood vessel activates these sensors, they send a signal to inform our central nervous system about this stimulus, and they influence the response that the body will use to correct this stretching.

There are two types of baroreceptors: 

• high-pressure baroreceptors, located in the aortic and carotid arteries
• low-pressure baroreceptors, situated in large veins and the heart

They act to increase or decrease the pressure, depending on the strength of the stretching signal received.

• Through the antidiuretic hormone: This is also known as vasopressin or ADH. Synthesised in a part of the brain called the hypothalamus and released in high concentrations to increase blood pressure.
• Through the Renin-Angiotensin-Aldosterone System: This relies on a circuit of hormones that act to increase blood pressure by the vasoconstriction of arteries and arterioles, releasing ADH or increasing the reabsorption of sodium in the kidneys.

High blood pressure (or hypertension) is the most common sign that something is wrong with our heart and blood vessels. A billion people suffer from high blood pressure all over the world, a number that has doubled over the last 40 years, especially in developing countries.³ By contrast, western countries have managed to decrease the number of people with high blood pressure, mainly through healthier habits and diets, availability of treatments and better healthcare³. But why is it important to control hypertension? Because high blood pressure increases the risk of suffering cardiovascular events such as:⁵ 

• Angina, Heart Attack and Heart Failure.
• Strokes and Transitory Ischemic Attack (TIA).
• Peripheral Arterial Disease, Aortic Disease. 

Cardiovascular diseases are the number one cause of death and disability worldwide. They were estimated to have caused 17.9 million deaths in 2019 worldwide, representing 32% of all global deaths.⁶  These numbers demonstrate how important it is to keep our blood pressure under control. To do so, we can change life habits such as reducing salt consumption and alcohol intake, stopping smoking and doing regular exercise. We can support these habits with the use of antihypertensive drugs. 

Effects of Garlic on Blood Pressure

Recent studies have shown the benefits of raw garlic, Kyolic aged garlic extract, garlic powder and garlic oil on our blood pressure. But what is this effect, and how does it work? Allicin, the main active compound in garlic, is thought to be behind garlic’s properties over blood pressure. Allicin is believed to prevent the production of angiotensin II, a compound responsible for increasing our blood pressure, along with increasing the production of hydrogen sulphide and nitric oxide, key components in blood pressure regulation.⁸  

Some studies suggested that Kyolic-aged garlic supplements significantly reduce blood pressure in hypertensive adults, both systolic and diastolic.⁷ Its efficacy is comparable to conventional standard blood pressure drugs, estimated to reduce the risk of cardiovascular events such as strokes, heart attacks or coronary disease by 16 to 40%.⁷ 

Other Benefits of Garlic

Kyolic-aged garlic extract has shown effectiveness in rejuvenating arteries. There is evidence to suggest that it can normalise cholesterol levels and blood thickness, therefore reducing the risk of blood clotting and thrombosis; however, more research is required.¹⁰ In addition to these cardiovascular benefits, the same studies have demonstrated that prebiotic Kyolic aged extract improves microbial richness and diversity in our gut, with a marked increase in the numbers of beneficial and immune-stimulating bacteria.¹¹

Different Forms of Garlic Intake

Overall, all forms of garlic have been shown to be beneficial, although aged garlic compounds appear to be the most beneficial. There are different forms of garlic intake that have been shown to reduce high blood pressure:⁸ 

• 188 mg of egg-yolk-garlic powder per day over 12 weeks.
• 400 mg of raw garlic a day for 6 months.
• 240-2400 mg of aged garlic extracts a day for 2-23 weeks.
• 600-2400 mg of garlic powder a day for 8-24 weeks.
• 12.3 mg of garlic oil per day over 16 weeks.

Side Effects

The consumption of garlic supplements and extracts has shown to have the following side effects:⁸

• Most common: garlic breath, taste and bad odour.
• Minor: stomach upset, reflux, gas.
• Rare: dry mouth, cough, ulcers, hot flushes.

Other Foods That Help to Lower Blood Pressure

Other foods can help to lower high blood pressure:⁹ 

• Dark chocolate (at least 60-70% dark): eating 1 to 2 squares of dark chocolate a day may help reduce our blood pressure and the chances of suffering a cardiovascular event.
• Certain plants and herbs: green and oolong teas, ginger root, celery, black bean, sesame oil and tomato extract.
• Products that are rich in potassium: sweet potato, spinach, tomato, bananas, apricots, avocados, low-fat milk and yoghurt, and whole grains.
• Products rich in protein and fibre: certain trials have shown that eating 100g of protein a day reduces 40% the risk of cardiovascular disease while adding regular fibre can decrease the risk by up to 60%.

Summary

Adding a regular intake of garlic to our diets helps to reduce high blood pressure and subsequently reduces the risk of suffering a cardiovascular event: the main leading cause of mortality worldwide, such as heart attacks or strokes. The regular intake of garlic, in its powder, raw or extract/supplement forms has been shown to significantly reduce both systolic and diastolic blood pressures in hypertensive subjects. In addition, garlic also may be able to help normalise cholesterol, reduce blood thickness, and improve the gut microbiome.