News Headlines
Lack of Vitamin D Increases Heart Attacks and Stroke
New research suggests that having low levels of vitamin D increases your risk of a heart attack, heart failure or stroke by over 60%. These findings, based on a study of more than 1,700 men and women with an average age of 59 years, also show that low levels of vitamin D are particularly harmful for those with high blood pressure. In addition, having both hypertension (BP above 140/90 mmHg) and a low vitamin D level significantly increases the risk of a heart attack or stroke, more than doubling the risk for people who were vitamin D deficient and normotensive. Why, remains uncertain, but may relate to calcium metabolism, or there may be a direct effect on circulatory tissues, as vitamin D receptors are found in blood vessel walls and in heart muscle cells.
Wang TJ et al.Circulation 2008 117(4):503-11
Soy Isoflavones May Improve Blood Pressure
New research suggests that genistein, an isoflavone found in soy, doubles the production of an enzyme needed to lower blood pressure naturally. The enzyme, endothelial nitric oxide synthase (eNOS), relaxes smooth muscle fibres lining small blood vessels, helping them to dilate and improving blood flow. This finding helps to explain previous findings that eating 40g soybean protein per day can reduce blood pressure by at least 7/5mmHg within 12 weeks, in people with hypertension, and by more than 2/1mmHg for those without hypertension
Hongwei Si, Dongmin Liu. Journal of Nutrition 2008. 138: 297-304
Tomatoes can lower cholesterol
Researchers from Finland have found that eating 30mg tomato sauce or drinking 400ml tomato juice every day can cut ‘bad’ LDL-cholesterol levels by 13 per cent, and increased LDL resistance to oxidation. These changes would be expected to reduce the risk of hardening and furring up of the arteries. Although only based on results from 21 healthy volunteers, this data supports the growing body of evidence for the health benefits of lycopene and other carotenoids found in tomatoes
Silaste ML et al. British Journal of Nutrition 2007. 98(6): 1251-125807
How Soy Lowers Cholesterol Levels
Eating a diet containing soy protein can lower ‘bad’ LDL-cholesterol, and scientists now suspect the reason why. It appears that certain peptide proteins found in soy can stimulate receptors on the surface of liver cells that bind to circulating cholesterol. This allows the liver cell to absorb the LDL-cholesterol for processing. As more LDL-cholesterol is taken up, levels circulating in the bloodstream fall
Cho SJ et al. Journal of Agricultural and Food Chemistry, 2007. 55(26):10599 – 10604
Latest News
New Nutritional Guidelines to Prevent Diabetes
Medical nutrition therapy significantly improves glucose control and reduce the risk of diabetes complications such as eye or kidney problems by 20% in people with type 1 diabetes and up to 40% for those with type 2 diabetes. As a result, the American Diabetes Association has updated its guidelines regarding medical nutrition therapy and diabetes. The new recommendations include suggestions that:
- All people with prediabetes or diabetes should receive individual nutritional therapy
- Nutrition counselling should be tailored to the needs of the individual according to their willingness and ability to make changes
- Intake of low-glycemic index foods that are rich in fibre, vitamins and minerals are encouraged
- Obtain carbohydrates from fruits, vegetables, whole grains, legumes, and low-fat milk
- Eat at least 2 servings of fish per week
- Weight loss – even if only modest - is vital for those who are overweight, to improve insulin sensitivity
- Either a low-carbohydrate diet or a low-fat, energy-restricted diet may be selected for short-term use of up to 1 year,
- Those following a low-carbohydrate diet (and arguably everyone) should have their blood cholesterol levels, triglyceride levels, kidney function and glucose control monitored.
- Regular physical activity (150 minutes/week) is helpful in achieving and maintaining weight loss.
- Alcohol intake should be restricted to no more than 1 drink per day for women and no more than 2 drinks per day for men, and should be consumed with food.
- Older adults with reduced energy intake may benefit from a daily multivitamin and mineral supplement.
American Diabetes Association. Diabetes Care. 2008;31(Suppl 1):S61-S78.
Fish oil reduces adverse effects of a high fat meal
Researchers have found that the omega-3 fish oil, EPA, helps to reduce the arterial stiffening effect of eating a high fat meal. Although a small study involving just 17 healthy males, this finding is yet another example of how fish oils are beneficial for the heart and circulation. Previous research shows that fish oils reduce abnormal blood clotting, improve heart rhythm and reduce the risk of heart attack and stroke – especially in people with pre-existing cardiovascular disease.
The volunteers ate a meal containing 51 grams of fat, either in the form of sunflower oil alone, or sunflower oil plus 5 grams of EPA. After a week, the meals were switched over (with a one week wash-out period in between). Researchers found that arterial stiffness significantly improved after eating the EPA enriched meal, with improvements lasting for up to three hours. This supports previous findings that omega-3 fish oil supplements can improve blood vessel elasticity.
Hall WL et al. Journal of Nutrition 2008. 138: 287-291