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Condition - High Blood Pressure

Hypertension

By Nutri People

What is blood pressure?

Each time your heart beats, it pumps blood through the arteries (large blood vessels). Blood pressure is the force of your blood pushing against the walls of the arteries. Blood pressure is highest when your heart pumps and is known as ‘systolic blood pressure’. When the heart is relaxing between beats your blood pressure falls. This is called the ‘diastolic blood pressure’. Your blood pressure reading uses these two numbers and is usually written as systolic blood pressure/diastolic blood pressure, for example 120/80 mm Hg (millimetres of mercury). 

What is high blood pressure? Bllod pressure check

Normal blood pressure is defined as a reading of 120/80 mm Hg or lower. High blood pressure (also known as hypertension) is defined as a reading of 140/90 mm Hg or higher. You are considered pre-hypertensive if your systolic blood pressure is between 120-139 mm Hg, or your diastolic blood pressure is between 80-89 mm Hg. 

Why is hypertension significant?

Hypertension is a well-recognised risk factor for cardiovascular disease. Most people can’t tell when their blood pressure is high, but high blood pressure can cause stroke, heart attack, heart failure, kidney failure and other serious problems. This is why it’s called the ‘silent killer’. High blood pressure has an even more damaging effect in those who smoke tobacco, who are overweight/obese, who have diabetes, high blood cholesterol levels or kidney disease. 

What are the causes?

In many cases, the cause of hypertension is unknown. However, certain factors can increase the risk of developing high blood pressure.

Risk factors

The following factors can play a role in the development of high blood pressure, especially in those with an inherited tendency to develop it: 

  • Sex. Males and postmenopausal females are at a greater risk.
  • Race. Americans and African Americans show a greater tendency.
  • Age. Middle aged and older.
  • Lifestyle factors. Smoking, sedentary lifestyle, obesity and stress.
  • Family history of high blood pressure.
  • Disorders. Diabetes, insulin resistance and kidney disease.
  • Dietary factors. Excess amounts of alcohol or salt in the diet, high intake of caffeine, high fat diet, a diet low in potassium, magnesium and calcium.
  • Medications.Some prescription drugs can increase blood pressure, including steroids, birth control pills, decongestants, non-steroidal anti-inflammatory drugs and diet pills.

Nutritional considerations

  • Fish oil. Evidence from studies and clinical trials suggests that long-chain omega 3 fatty acids (EPA and DHA) may help protect against cardiovascular disease. One study, in the scientific journal Hypertension, showed that a high intake of long-chain omega 3 fatty acids significantly reduced blood pressure (systolic and diastolic) in overweight individuals taking medication for their high blood pressure. In this study, combining a high intake of omega 3 fatty acids with a weight loss regimen proved to have an additive effect on reducing blood pressure. Another double-blind, randomised, placebo-controlled study in the journal Hypertension suggests that DHA is mainly responsible for the blood pressure-lowering effects of omega 3 fatty acids. Several studies also suggest a possible link between inflammation in the body and elevated blood pressure. Omega 3 fatty acids may help support anti-inflammatory processes. Fish oil is an excellent source of omega 3 fatty acids.
  • Magnesium. Studies suggest that low blood magnesium levels may increase the risk of developing hypertension. Hypertensive individuals taking diuretics (drugs used to treat hypertension) for a long time are at a risk of magnesium deficiency.
  • Calcium. Randomised clinical trials suggest that calcium may help support systolic and diastolic blood pressure readings within a normal healthy range.
  • Co-enzyme Q10 (also known as CoQ10 or ubiquinone) is an oil-soluble nutrient and antioxidant, found naturally in the energy-producing structures inside our cells, known as the mitochondria. Double-blind, placebo-controlled trials suggest that CoQ10 may help to support healthy blood pressure, within normal ranges.
  • Olive leaf. Research has shown that a chemical called oleuropein can relax and dilate blood vessels. Oleuropein is a component of olive leaf. Another study, published in the journal Phytotherapy Research, suggests that substances present in olive leaf may help support healthy blood pressure within normal ranges.
  • Vitamin D. Vitamin D deficiency is common and is mainly caused by reduced sun exposure (vitamin D is actually produced by an exposure of skin to sunlight). There is an increasing amount of scientific evidence implicating vitamin D deficiency in an increased risk of hypertension. Early evidence showed that people living at higher latitudes throughout the world (areas where the sun’s rays are not intense enough  to make sufficient amounts of vitamin D in the skin) were at greater risk of developing hypertension. Other studies have shown that increasing blood concentrations of vitamin D in people with high blood pressure results in a reduction in both systolic and diastolic blood pressure. But how does vitamin D achieve this? Well, there are vitamin D receptors (sites within our bodies, where vitamin D can attach) present on blood vessels.  When vitamin D attaches to, and activates, these receptors, they relax (get wider). Vitamin D has also been shown to support the normal production of an enzyme produced by the kidney, called renin, which can increase blood pressure.
  • Alpha lipoic acid and acetyl-L-carnitine. Mitochondria are the energy-producing structures inside our cells. There is growing evidence that disturbances in the function of mitochondria may contribute to the development of hypertension. A study in The Journal of Clinical Hypertension suggests that alpha lipoic acid and acetyl-L-carnitine may help provide support for normal mitochondrial function and healthy systolic blood pressure, within normal ranges.Nutritional factors for reducing high blood pressure
  • Lycopene. Carotenoids are naturally-occurring pigments with antioxidant activity. Lycopene is a carotenoid that gives tomatoes, watermelon and pink grapefruit their red colour. Studies suggest that lycopene may provide support for healthy blood pressure levels, within normal ranges.
  • Nitric oxide.Recent research suggests that the blood vessels of people with normal blood pressure relax much more efficiently than the blood vessels of those with high blood pressure. Blood vessels that don’t relax efficiently may not only increase an individual’s risk of hypertension, but also of a heart attack and stroke. Nitric oxide (NO)is a natural molecule that our body produces, that performs many tasks. One of these is to help relax blood vessels, which means the blood vessels get wider and allow more blood through. Widening of blood vessels will also help to reduce blood pressure. L-arginine is an amino acid used by the body to produce NO. Many people with high blood pressure will know that it has a tendency to keep climbing, rather than stay at one level. Why? A study at UC Irvine College of Medicine suggests that high blood pressure actually inactivates NO, which leads to further increases in blood pressure and a vicious circle sets in. The researchers showed that as blood pressure increases there is also an increase in free radical production and these free radicals inactivate NO. Antioxidants may help to mop up excess free radicals. Vitamin C is an antioxidant nutrient. A placebo-controlled, double-blind study, published in the medical journal The Lancet by scientists at Boston University School of Medicine and the Linus Pauling Institute at Oregon State University, suggests that vitamin C may help support blood pressure levels, within a normal range. A more recent study from the University of California, Berkeley, showed that women with the highest blood vitamin C levels had lower systolic and diastolic blood pressures than women with the lowest vitamin C levels. Apart from mopping up free radicals, which may help protect the body’s normal levels of NO, a study in The Journal of Biological Chemistry has shown that vitamin C may also help to increase levels of a substance called tetrahydrobiopterin, which is needed by the body to produce NO. Finally, a study in the journal Nutrition Research showed that garlic increases the production of NO in the cells lining the walls of blood vessels and that this effect of garlic was enhanced by the addition of vitamin C.

Dietary advice

  • Carotenoids may help to prevent hypertension. Foods rich in carotenoids include carrots, pumpkin, tomatoes, spinach, sweet potato, kale, mustard greens, broccoli, Brussels sprouts, yellow corn, peas, collards, dandelion and turnip greens, papaya and watermelon.
  • Kiwi fruit may be helpful, according to scientists from the University of Oslo in Norway, who showed a link between eating kiwi fruits and lower blood pressure. Kiwi fruits are rich in carotenoids and contain potassium.
  • Dark chocolate. Good news for chocolate lovers – researchers have found evidence that the consumption of dark chocolate may, in fact, be a healthful practice. Very recently, Dr Karin Ried from Adelaide University in Australia and her team, writing in the journal BMC Medicine, combiDietary advice for reducing high blood pressurened the results of 15 studies looking at the effects of cocoa, as chocolate or as a drink, on blood pressure. They found that, for people with hypertension, eating dark chocolate could reduce blood pressure by up to 5%. The reduction in blood pressure was comparable to the known effects of half an hour of moderate exercise daily and could, in theory, reduce the risk of a cardiovascular event (heart attack or stroke) by about 20% over five years. There was no reduction in blood pressure for those with normal levels. Chemicals called flavanols may help to explain the effects of dark chocolate on blood pressure. Flavanols are found in foods like green tea, red grapes, berries, apples and chocolate. Eating flavanol-rich foods may result in an increase in the levels of NO, which helps to relax blood vessels and, consequently, may lower blood pressure. In order to obtain the highest flavanol content, go for very good quality organic dark chocolate containing a minimum of 70% cocoa. But remember to consume in moderation!
  • Potassium.Studies suggest that higher dietary intakes of potassium are associated with significantly lower blood pressure. Potassium-rich foods include fruits and vegetables. Dried fruits, including raisins and prunes, are also rich sources.
  • Calcium may have a beneficial effect on blood pressure. Dairy products are high in absorbable calcium. Certain vegetables also provide absorbable calcium. Kale family vegetables (broccoli, bok choy, cabbage, mustard and turnip greens) contain calcium that is as bioavailable as milk.
  • When preparing foods grill, bake or stir fry with extra virgin olive oil.
  • Eliminate fried foods, alcohol and processed foods.
  • Limit caffeine intake. Evidence from randomised, controlled trials suggests that chronic coffee and caffeine consumption raises systolic blood pressure, particularly in those with hypertension.
  • Beneficial foods for those with hypertension include celery (researchers at the University of Chicago Medical Centre have identified a chemical, called 3nB, as the factor in celery responsible for its blood pressure lowering effects); garlic and onions (may help maintain healthy cholesterol levels); nuts, including walnuts, and seeds (good sources of fibre and healthy fats); cold water oily fish, including sardines, mackerel and salmon (good sources of omega 3 fatty acids and vitamin D); green leafy vegetables (high in calcium and magnesium); flax seeds, whole grains and legumes (for their fibre); broccoli and citrus fruits (for their vitamin C).
  • Follow the DASH (Dietary Approaches to Stop Hypertension) diet, which may help to keep blood pressure in the healthy range. The DASH diet was developed by researchers at the National Institute of Health’s National Heart, Lung and Blood Institute. It’s based on a research study that identified foods that affect blood pressure. Basically, this diet involves consuming generous amounts of fruits, vegetables and low-fat or fat-free dairy products (good calcium sources). Such a diet is high in potassium, calcium, magnesium and fibre and low in sodium, total fat, saturated fat and cholesterol. The DASH diet has been shown to replace the need for first-line antihypertensive drugs in those newly-diagnosed with hypertension. It has also been shown to help reduce both systolic and diastolic blood pressure in those with hypertension.
  • Restrict dietary salt intake and avoid hidden sources of salt. Salt is a combination of sodium and chloride. Studies have shown an association between increased sodium intake and increased blood pressure. Some people’s bodies are more sensitive to the effects of sodium than others. If you are sodium sensitive, your body retains sodium more easily and the sodium starts to accumulate in your blood. Because sodium has the ability to attract and hold water, your blood volume increases, leading to an elevation in blood pressure. If the pressure is too high, the blood vessels can burst like a balloon. This is how high blood pressure causes stroke and kidney disease. There is also evidence that salt restriction is more likely to reduce blood pressure in these ‘sodium-sensitive’ individuals. Sodium sensitivity has been reported to be more common in obese and insulin resistant individuals, elderly and female hypertensive patients.  Where does the sodium come from? Processed and prepared foods are typically high in salt and also in additives that contain sodium. Many recipes use salt and many people add salt to their food at the table. Read the food labels while shopping, which lists the amount of sodium (or salt) in each serving. It also lists other ingredients high in sodium including baking soda and powder, disodium phosphate, sodium alginate, sodium nitrate or nitrite and monosodium glutamate (MSG). The UK Food Standards Agency defines a food low in salt if it has 0.3g salt (or 0.1g sodium) or less, per 100g of food. You can eat more of these foods. Medium is 0.3-1.5g salt (or 0.1-0.6g sodium), per 100g of food. Eat smaller amounts of these, occasionally. High is 1.5g salt (0.6g sodium) or more, per 100g of food. Avoid these completely. Be careful with foods labelled ‘reduced sodium’ or ‘reduced salt’ as they may actually still contain a lot of salt. Some ideas to help you eat less salt include:
  1. Always read the food labels for sources of sodium or salt.
  2. Try to avoid processed foods. If you do occasionally buy processed foods, choose those that are low in sodium.
  3. Try not to add salt to your food when cooking (or use very small amounts). Use herbs and spices to flavour foods, including ginger, chilli, lemon juice and fresh or dried herbs (turmeric, cumin seeds, coriander, fennel, bay leaf, etc).
  4. Reduce your use of sodium-containing condiments, including soy sauce, stock cubes, ketchup, mustard, sauces, salad dressings, etc.
  5. Processed meats, smoked meat and fish, bread and breakfast cereals can all contain a lot of hidden salt.
  6. If you decide to use low sodium salt substitutes, use sparingly and check with your doctor first if you have kidney problems or diabetes and if you are taking medication for congestive heart failure or high blood pressure.
  7. Remember to decrease your intake of added salt gradually, to allow time for your taste buds to adjust to the new level of salt.

Lifestyle advice

  • Maintain a healthy weight (your Body Mass Index should be below 25). Weight loss can improve blood pressure.
  • Consume alcohol in moderation only. Metabolism of alcohol may increase blood pressure.
  • Exercise regularly. One study showed that 60-90 minutes, weekly, of aerobic exercise may be sufficient for producing maximum benefits. Another study found that taking four 10-minute exercise periods of brisk walking daily significantly improved blood pressure.
  • Stop smoking. Smoking is a risk factor for cardiovascular disease.
  • Control stress levels. Practice relaxation techniques including yoga, meditation or breathing exercises.
  • Acupuncture. The results of some randomised, controlled studies suggest that acupuncture may be helpful in managing blood pressure. Studies conducted in China suggest that acupuncture may exert its effects on blood pressure by influencing the hormones that regulate blood pressure. Another study suggests that it may increase the levels of NO. 

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