According to Canadian scientists, eating lentils could reverse the blood vessel changes that lead to high blood pressure. Their research did not involve humans, but a strain of rat who normally develop spontaneous hypertension through inheriting inelastic arteries. In their study, rats fed a lentil-based diet (30% of total feed) for 4 weeks had significantly lower average blood pressure (144 mmHg versus 171 mmHg) than those fed a non-lentil diet. Overall, blood pressure in the lentil-fed spontaneously hypertensive rats only rose by 1/10 mmHg compared with a rise of 26/30 mmHg in the spontaneously hypertensive rats who were not fed lentils.
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Lentils and blood pressure
The prevention of hypertension from eating lentils was attributed to improved elasticity of blood vessel walls, which continued to react in the same way as blood vessels in normal, healthy rats. In contrast, those fed a lentil-free diet developed the characteristic blood vessel changes that caused their blood pressure to rise. A mixture of red and green lentils had the greatest blood pressure lowering effect and, interestingly, the same benefits were not seen in rats fed related legumes such as beans, peas or chickpeas.
Lentils are an edible legume that vary in colour from red, green, yellow and gold through to brown and black. Their greatest blood pressure lowering effects is believed to result from their high level of antioxidant polyphenols which are present at a concentration of around 3700 mg per 100g weight. These antioxidant polyphenols are known to lower cholesterol levels and to increase the elasticity of artery walls among other health benefits.
Some polyphenols also appear to lower blood pressure by blocking the effects of angiotensin converting enzyme (ACE) in a similar way to ACE inhibitor antihypertensive drugs.
Other legumes that have high antioxidant levels include red kidney beans, pinto beans and black beans.
Antioxidant ORAC score per 100g
|Red kidney beans||14,413|
Lentils are also a rich source of oestrogen-like plant hormones, mainly lignans such as those found in sweet potato and flaxseed, plus useful amounts of isoflavones. Lentils also supply protein, fibre, carotenoid pigments, B vitamins and minerals such as magnesium and potassium, all of which have beneficial effects on blood pressure.
Lentils and cardiovascular health
Legumes are an important component of the Mediterranean diet and the DASH (Dietary Approaches to Stop Hypertension) Diet.
Human studies looking at the intake of legumes such as lentils have found that people who eat the most legumes are 34% less likely to experience a heart attack or stroke than those eating the least, after taking other factors into account.
In 26 people with peripheral arterial disease, eating ½ cup non-soy legumes (beans, peas, lentils, chickpeas) per day for 8 weeks, experienced a significant increase in arterial dilation and increased blood flow, as well as an 8.7% reduction in LDL-cholesterol.
A study looking at dietary factors in almost 800 older people aged 70 and over, found that every 20g increase in average daily intake of beans (including lentils) was linked with an 8% lower risk of death during the seven-year follow-up period – a protective effect that was even higher than for fish and olive oil.
How to eat more lentils
While eating 30% of food in the form of lentils for 4 weeks had no adverse effects on the hypertensive rats, this definitely would not constitute a healthy, balanced diet for us. However, eating lentils regularly, three or four times a week, may benefit overall health, especially on meat-free days.
Add lentils to soups, stews, casseroles, flans, rissoles and use in dishes such as baked lentil loaf. In Asia, lentils are used to make Dhal which, when served with rice helps to provide a balanced intake of amino acids.
The carbohydrate in lentils is mostly in the form of slowly digested starch which gives them a low glycemic index (GI) and makes them a great, filling addition to a healthy Mediterranean-style DASH diet for people with high blood pressure.
Here are some of my favourite lentil recipes, including Rick Stein’s Spanish Lentils, Gordon Ramsay introducing Grey Mullet with Puy Lentils, Nigella’s Lentil & Chestnut Soup, and Chef Buck’s Lentil & Ginger soup. Fabulous.
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