
by Meredith Beil & Alice Downing APD, MDiet & BHumNutr
Effects of Diet
and Lifestyle on Blood Pressure
High blood pressure (hypertension) is extremely
common in western society. As we age, the incidence of hypertension generally
increases. More than 50% of our population over the age of 60 has high blood pressure.
This increases to approximately 90% of our population by age 80-85.
Hypertension can increase risk of significant
cardiovascular and kidney disease, so it is important that blood pressure is
maintained between <130/85 and <140/90 for people over 65 who do not have
chronic disease complications. Medication is an important and effective
treatment, however, there are dietary and lifestyle factors that should be
addressed in order to achieve an optimal blood pressure.
Weight Loss
There is strong scientific evidence that weight
loss can decrease blood pressure. If overweight, losing body fat can reduce blood
pressure in the range of 5-20mmHg per 10kg lost. Weight management can be the
difference between normal blood pressure and hypertension. Aim to achieve and
maintain a healthy body weight with a waist circumference of <80cm for
females and <94cm for males (<90cm Asian males); or if you are overweight
aim to lose at least 5-10% of body weight. Consult your GP or dietitian for
support regarding healthy weight loss.
Physical Activity
Regular exercise or physical activity can reduce blood
pressure independent of its weight loss effects. A reduction of 2-4mmHg can be
expected by initiating an exercise routine such as a 30 minute walk or bike
ride five days per week. Most people
require a minimum of30 minutes of moderate to vigorous intensity exercise, on
five or more days per week, to achieve health benefits of regular exercise.
Dietary Sodium
Consumption of sodium in the form of salt (sodium
chloride) in the western diet is one of the most significant causes of
age-related hypertension. Sodium is available in many forms such as rock salt,
sea salt and garlic salt, and monosodium glutamate (MSG). There is no benefit
in choosing sea salt or Himalayan salt over table salt.
Approximately 80% of the sodium in a typical
western diet comes from processed foods, while 12% is naturally occurring in
food, and 8% is added in cooking, or at the table. Choose packaged foods that
are labelled as “salt reduced” or “no added salt”, and read the nutrition information
panel to select low sodium foods with 120mg of sodium per 100g or less. Australians
consume sodium at a level that far exceeds the recommended daily intake of 2,300mg
per day. All Australians, particularly those who have hypertension, should aim
to reduce their intake. Choose fresh
foods as often as possible to limit sodium intake.
Fruit and Vegetables
A high intake of fruit and vegetables is directly
associated with reductions in blood pressure. Studies show the greatest positive
effect on blood pressure occurs in people who eat at least 9 serves (about 5
cups) of fruit and vegetables daily. High dietary potassium, which is found
naturally in fruit and vegetables, opposes the effects of dietary sodium and
has a beneficial effect on blood pressure. Frozen and canned fruits and
vegetables are good alternatives to fresh produce, but please ensure they do
not have added sugar or salt.
Dietary Fat
Consuming a low fat diet (<30% of energy intake)
and limiting intake of saturated fat (<10% of energy intake) is recommended
for most people and has a beneficial effect on blood pressure. Choose products
that are labelled as “reduced fat” or “low fat”, to reduce intake of total fat
and saturated fats. Two to three serves of oily fish (salmon, sardines or tuna)
per week can be of benefit in people with hypertension. High strength fish oil
supplements are also effective in improving cardiovascular health Ask your
pharmacist for a product that provides 3g fish oil per day.
Low Fat Dairy
Three serves (about 3 cups) of low fat dairy food per
day is consistent with lowering of blood pressure. Non-fat or reduced fat milk
and yoghurt is recommended for daily consumption, however ice cream and hard
cheese should be limited as these are energy dense foods. One serve of cheese
is equal to 40g (2 slices) whilst a serve of ice cream is 100g (2 scoops). Choose
reduced fat ice cream and cheese, and limit to 4 serves per week.
Alcohol Consumption
Individuals who consume 3 or more alcoholic drinks
per day experience hypertension at a level 3 times higher than non-drinkers.
Binge drinking is linked to a higher incidence of cardiovascular death and
stroke, and alcohol directly increases blood pressure and can interact with some
medications. Alcohol is high in kilojoules and is often a major contributor to
being overweight or obese, thus both directly and indirectly contributing to
elevated blood pressure.
Each standard drink (10g alcohol) increases blood
pressure irrespective of the type of alcoholic beverage and although the flavonoid
components of red wine are beneficial to health they have not been shown to
reduce alcohol related hypertension. Australian adults should consume no more
than 2 standard drinks (20g alcohol) on any occasion to reduce lifetime risk of
harm from alcohol-related disease or injury.
Avoidance of Smoking
Smoking directly causes constriction of blood
vessels, which directly increases the pressure exerted on your blood vessels
when your heart beats. Therefore smoking directly increases your blood
pressure. Smoking cessation (or never starting) is of great benefit to
sufferers of hypertension. Speak to your GP or pharmacist about smoking
cessation options.
Relaxation
Acute emotional stress is known to increase blood
pressure. Relaxation techniques such as meditation, yoga and tai chi can
greatly benefit overall health and reduce hypertension.
Dietary
Recommendations for Blood Pressure Management
- Reduce sodium intake
- Choose reduced salt/no
added salt breads, cereals and canned
foods
- Minimise intake
of processed foods
- Gradually reduce the salt in your diet and your
taste buds will soon adapt
- Use fresh or dried
herbs/spices/garlic/ginger/chilli to add flavour to meals
- Increase potassium intake through fruit and
vegetables
- Eat 9 serves of
fruit and/or vegetables per day (5 cups or more)
- Including at least 4 serves of fruit (2 cups or
more)
- Consume three serves of low fat dairy products
each day
- Choose milk or yoghurt
- Eat reduced fat cheese or ice cream less often
- Reduce saturated fat intake
- Choose low-fat/reduced
fat animal products (dairy, meat)
- Limit fried food,
take-away, chips, biscuits
- Consume whole-grains, fish and nuts regularly
- These food contain mono and poly unsaturated fats
- Consider taking a fish oil supplement
- Choose lean meats, and limit red meat intake
- Lean
meats: chicken, pork, kangaroo
- Choose
red meat 2 days per week
- 1
serve of lean meat = 65-100g; e.g. a
small steak or 2 small chops
By making these diet and lifestyle changes you can
significantly lower your blood pressure, and you can enjoy many additional health
benefits!
References
1.
Heart
Foundation of Australia. www.heartfoundation.org.au;
2.
7th report of
the joint national committee on prevention, detection, evaluation and treatment
of high blood pressure. Hypertension 2003:42:1206-1252.;
3.
National
Nutrition Survey ABS catalogue No 4805.0.,
4.
Cochrane Review
2000. (2:CD000484);
5.
Jung R. British
Medical Bulletin 1997:53:307-21.;
6.
Nowson CA, et
al. Blood pressure change with weight is affected by diet type. Am J Clin Nutr
2005;81(5);983-9.;
7.
Puddey IB,
Beilin LJ. Alcohol is bad for blood pressure. Clin Exp Pharmacol Physiol; 2006;
Sep 33(9);847-52.;
8.
Meneton et al
2005. Links between dietary salt intake, renal salt handling, blood pressure
and cardiovascular disease. Physiol Rev:85(2):679-715.;
9.
INTERSALT study
1988 BMJ;297:
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