By LOUISE CARR, Associate Editor and Featured Columnist
The good news is a diet that benefits blood pressure also, more often than not, helps lower blood pressure. An ideal diabetic and blood pressure-lowering diet includes high levels of fruit, vegetables and whole grains, low levels of saturated fats and cholesterol, good levels of low-fat dairy and monosaturated fats, and foods that keep your blood sugar levels even throughout the day.
This is similar to the DASH (Dietary Approaches to Stop Hypertension) diet, which also limits sodium consumption and in effect helps control both diabetes and high blood pressure.
We've scoured the scientific research to highlight the areas of your diet that need special attention and the super-foods to lower blood pressure and control your diabetes.
If you put just one diet change into action right now, let it be salt reduction. If you're living with diabetes, reducing the amount of salt you consume is key to lowering your blood pressure and preventing serious health complications.
In the 2001 Cochrane review of 13 studies on adults with type 1 and type 2 diabetes, researchers found that reducing salt intake by 8.5g a day could lower blood pressure by 7/3mmHg - a similar result to taking blood pressure-lowering medication.
Many of us eat way too much salt. The American Heart Association suggests you should consume just over half a teaspoon of sodium a day. Clear the salt shaker from the table and avoid adding salt to your dishes. And steer clear of processed and packaged foods, sauces and snacks - many of these convenience foods are crammed with salt.
2. Add Herbs and Spices
If you find food bland after cutting out the salt, use a variety of herbs and spices to flavor your food instead.
Tasty salt substitutes include ground cumin, garlic powder, curry powder, basil, oregano, celery seed, onion powder and pepper.
Herbs and spices may have an added effect apart from making your food taste good. For example, cinnamon has been shown to reduce fasting blood sugar levels.
A 2003 study from the NWFP Agricultural University, Peshawar, Pakistan reported that cinnamon produced lower levels of fasting glucose, triglycerides, LDL cholesterol and total cholesterol after 40 days. Levels continued to drop for the following 20 days.
Garlic has been widely reported to lower blood pressure and it gives your food a powerful flavor.
Herbal supplements may help too. A 2006 study from the University of Reading, England looked at hawthorn's effects on hypertension in patients with type 2 diabetes who were taking prescribed drugs. Those who took 1,200 mg of a hawthorn extract supplement each day for 16 weeks showed greater reductions in blood pressure than the control group.
3. Check Your Carbohydrate Intake
Carbohydrates make up one of your major food categories if you suffer from diabetes, but it's important to eat the right kind of carbohydrate particularly if you also suffer from high blood pressure.
Carbohydrates provide fuel in the form of glucose - energy for all the cells in your body. But it's important to eat the right amount of carbohydrates at each meal because they have the most immediate effect on your blood sugar levels. Check with your health care provider to find the right levels for you.
Choose complex carbohydrates, found in nuts, vegetables, whole grains and beans, rather than simple refined sugars, white breads and fruit. Diets high in whole grains are good for achieving weight loss and reduce the risk of high blood pressure, according to a 2008 study from a team of Penn State researchers at University Park and the College of Medicine.
In the study, the group of obese participants who ate a whole grain diet experienced a 38 percent drop in C-reactive protein levels in their blood - a marker thought to put you at a higher risk for diabetes and hypertension as well as cardiovascular disease.
Great grains for regulating blood sugar include whole grain barley, whole grain rye and oats. One way of starting your day on the right foot is to have a mixture of these grains for breakfast.
4. Get Enough of the Right Kind of Fiber
When you eat a lot of fiber, experts believe you are at lower risk of obesity, high blood pressure and diabetes complications. There's one particular fiber superstar when it comes to delivering both blood pressure and insulin benefits - oat bran.
A 1994 study from the University of Ottawa, Ontario, Canada found the compound in oat fiber, beta-glucan, lowers blood sugar and insulin levels in type 2 diabetics. A diet rich in oat fiber may be of benefit to diabetics in order to lower levels of blood sugar throughout the day.
In a 2002 study from the University of Minnesota Medical School, Minneapolis whole grain oat-based cereals significantly reduced the need for blood pressure lowering medication - 73 percent of participants in the oats group versus 42 percent in the control group were able to stop or reduce their medication by half.
Other fiber-rich foods include fresh fruit and veggies, brown rice, cooked beans and peas, and whole grain bread. (Read more about why oatmeal is one key to a long life.)
5. Choose the Right Amount and Type of Fat
When you have diabetes, you have a higher than average risk of developing cardiovascular disease and a diet low in saturated fat is one of the best ways to prevent heart complications occurring.
When you limit calories from fat you are also more likely to lose weight, cutting down one of the linked risks of heart attack for high blood pressure and diabetes sufferers. One 2006 study from the Physicians Committee for Responsible Medicine, the George Washington University and the University of Toronto showed a low-fat vegan diet was more effective than a standard diabetes diet and could be more effective than therapy with oral diabetes drugs in managing diabetes blood sugar control and weight control.
Another 1997 study by the Johns Hopkins University found a diet of low-fat dairy foods and reduced levels of saturated and total fat significantly lowered the blood pressure of 459 adults during an eight-week period.
Eat the leanest cuts of meat or, better yet eat fish. Choose low-fat dairy but make sure you include the dairy in your daily carbohydrate count. Bake, grill, roast or boil foods rather than fry them or use a low-fat vegetable oil or olive oil cooking spray. Add nuts rich in heart-healthy oils such as walnuts.
6. Eat a Diet Rich in Magnesium
Foods high in magnesium can help lower blood pressure and control your blood sugar levels at the same time.
A 2006 study from Harvard Medical School and Brigham and Women's Hospital in Boston followed women health professionals over 10 years and found those whose diets had the highest levels of magnesium were the least likely to suffer from high blood pressure, and vice versa.
Another 1994 study by the Erasmus University Medical School, Rotterdam found oral supplementation with magnesium lowered blood pressure in subjects with mild to moderate hypertension. If you're diabetic you may be deficient in magnesium.
One 2003 study from the Medical Research Unit in Clinical Epidemiology of the Mexican Social Security Institute, Durango, Mexico showed magnesium supplements enhanced blood sugar control and insulin sensitivity in people with type 2 diabetic patients and low serum magnesium levels.
Top foods for magnesium include sunflowers seeds, almonds, cashews, halibut, spinach, soybeans, lentils, whole grains, avocado, shrimp, dried fruits and oatmeal. Zucchinis are high in magnesium and, new research shows, they have special nutrients which are effective in controlling blood sugar. (Read more about zucchini's ability to control blood sugar.)
7. Keep Your Vitamin D Levels Up
When you're looking at your vitamin and mineral intake, pay attention to your levels of Vitamin D - low levels of Vitamin D have been linked with poor blood sugar management and an increased risk of diabetes.
Vitamin D-3 is particularly important. A 2001 birth-cohort study from the Institute of Child Health, London, UK found dietary Vitamin D supplementation is associated with a reduced risk of type 1 diabetes. Food sources of Vitamin D include oily fish such as salmon and low-fat dairy products, especially milk. These foods are also good for helping lower your blood pressure.
8. Take Vitamin C...
People with diabetes often have lower-than-average levels of Vitamin C, perhaps caused by higher blood sugar levels harming the uptake of Vitamin C in cells. A 2007 study from the University of Warwick, UK found Vitamin C may help reduce diabetes complications by helping eradicate free-radicals that are over-produced when you have diabetes.
However, they also found a blood pressure lowering drug had the same effect and that treatment was only effective in the long-term. One 2000 study by the University Division of Medicine for the Elderly, University of Leicester, UK discovered that Vitamin C may also have modest effects on lowering high systolic blood pressure in older adults.
9. …But Don't Neglect Fruit and Vegetables
Eating a well-balanced diet high in natural fruit and vegetables is key to lowering blood pressure and maintaining blood sugar levels, and no amount of vitamin supplementation will be as effective. Diabetes organizations suggest eating a serving of fruit at each meal and one or two servings of vegetables at both lunch and dinner.
Try beet juice. One 2008 study from the London School of Medicine, UK found drinking two glasses of beet juice a day (500 ml total) could lower blood pressure by as much as 10 points within three hours. However, surprisingly, using anti-bacterial mouthwash before drinking the concoction cancels out the positive blood pressure-lowering effect.
10. Chow Down on Chocolate?
Chocolate? Really? A 2005 study from the University of l'Aquila in Italy says yes, and suggests that eating 100g of antioxidant-rich dark chocolate a day for 15 days lowers blood pressure as well as improves the diabetic body's ability to metabolize sugar. Go easy, though - excess calories from chocolate and the sugar rush you set off in your body will undo any blood pressure and blood sugar benefits.