Obesity

A distinct relationship between body weight, blood pressure and CVD have been well documented, and the relative risk of developing hypertension, a risk factor for CVD, increases as body mass index (BMI) increases.⁴ Modest weight loss of approximately 10% of body weight can normalise blood pressure. A recent review of the Trials Of Hypertension Prevention (TOHP) phase II revealed that a weight loss of approximately 5 kg can result in a significant reduction in blood pressure.⁵ Advice about weight loss is essential. Maintaining weight loss is the greatest difficulty faced by patients. A healthy diet and regular exercise are essential for maintaining ideal BMI.

Recently it has been reported that people lose weight by just eating fewer calories, regardless of where those calories come from.^{6, 7} In this US study it was reported that after 2 years, 811 overweight adults randomised to 1 of 4 heart-healthy diets, each emphasising different levels of fat, protein, and carbohydrates, showed similar degrees of weight loss. On average, participants in the study lost 6 kg in 6 months, but gradually began to regain weight after 12 months, regardless of diet group. Briefly, the diets tested in the study included the same types of foods, but in different proportions, and were tailored to patients such that overall calorie consumption was reduced by approximately 750 calories per day, with each diet including a different macronutrient composition:

Prevention

The public and health professionals must implement comprehensive preventative programs that address lifestyle and nutritional issues if it is to achieve a significant reversal of the increasing incidence of CVD worldwide.¹ The major focus is currently on treatment of CVD, however, there is increasing interest in dealing with the factors responsible for this disease, but more needs to be done. More is known about the factors responsible for CVD than most other diseases and hence it lends itself well to interventions with primary and secondary prevention.

The Australian Heart Foundation website provides extensive public and health professional information on risk factors, prevention and lifestyle strategies for hypertension and CVD.⁸

Family lifestyle intervention for children

Obesity in children and adolescence is a growing problem in virtually every developed country and the prevalence is rising. Extrapolation from current US data found adolescent overweight is projected to increase the prevalence of obesity in adulthood (35-year-olds) in 2020 to 30–37% in men and 34–44% in women, which will consequently increase the incidence and risk of coronary heart disease (CHD), cardiac events and deaths in young adults and the middle aged.¹⁸ Management of the child to lose weight needs to focus on lifestyle interventions such as modifying diet, physical activity and behavioural therapies within the whole family. A recent Cochrane review evaluated the efficacy of lifestyle, drug, and surgical interventions to treat obesity in childhood.¹⁹ A total of 12 studies were directed at lifestyle interventions (physical activity and sedentary behaviour), 6 studies addressed diet and 36 evaluated behaviourally oriented treatment programs. This review concluded that family-based lifestyle interventions that modify diet and physical activity and include behavioural therapy can significantly help obese children lose weight and maintain that loss for at least 6 months compared to standard care or self-help alone.

Depression and social isolation

Depression and social isolation are strongly associated with CVD and can have a major influence on prognosis.²² The impact of depression and social isolation is of a similar order to conventional risk factors such as smoking. A study of up to 500 patients hospitalised for acute coronary syndrome found that the onset of depression immediately following an acute cardiac event significantly influenced the long-term survival and illness severity of the patient.²³

The Heart and Soul Study is a prospective cohort study of 1017 outpatients with stable CHD followed for an average period of 4.8 years.²⁴ After adjustment for co-morbid conditions and disease severity, depressive symptoms were associated with a significant 31% higher rate of cardiovascular events compared with those with no depression, which was largely explained by negative behaviour patterns such as physical inactivity.

Worrying and mental stress are also a risk factor for cardiac events, CHD and accelerates atherosclerosis according to studies.^{25, 26}

Social isolation is a difficult problem to deal with and requires taking an extensive family history about family and friends and usually assistance and support from other health professionals and support groups.

A cohort of 13 000 women and men demonstrated a doubling of the coronary risk factor with social deprivation over a 10-year period.²⁷ Having a close friend for regular support when needed can reduce the risk of subsequent myocardial infarction by 50%.²⁸

An expert working group for the National Heart Foundation of Australia did a systematic review of the literature and found strong and consistent evidence to indicate depression, social isolation and lack of quality social support is associated with the causes and prognosis of CHD.²⁹

Owning a pet may help pet owners survive longer after a heart attack and reduces heart rate variability according to a US study of 100 patients following a myocardial infarction when compared with non-pet owners.³⁰

Social support

The Framingham Heart Study social network followed up 4739 individuals over a 10-year period and found that people’s degree of happiness was determined by the happiness of others whom they are connected with, being surrounded by happy people and geographical proximity in close range.³¹ For example, a happy friend who lives within 1.6 km increases the probability that a person is happy by 25%. Similar effects were seen with partners, siblings who live close and next door neighbours, but not seen between co-workers. Effects are not seen between co-workers and happiness declined with time and geographical separation.

Unhappy marriage

An interesting 5-year follow-up study found that women with CHD had a 3-times higher chance of major cardiac events and death over the 5 years if they had a stressful marital or cohabiting relationship.³² Negative relationships can increase the likelihood of cardiac events and in 1 study this risk was estimated to be as high as 34% compared with low level negativity.^{33, 34} A good marriage also improved survival in women with heart failure.³⁵

Anxiety

Anxiety and panic disorder are known risk factors for CHD and sudden death in both men and women. The Nurses Health Study of over 72 000 female nurses with no history of CHD or cancers, followed up over 12 years, found that high levels of anxiety raised the risk of fatal CHD by 1.6 times and sudden cardiac death by 1.8 times compared with women with lowest scores for anxiety. Of interest, the data on all women found that up to 28% had severe phobic anxiety scores, who demonstrated highest baseline cardiovascular risk, particularly in women who did not exercise, were more likely to smoke, have a history of diabetes, high cholesterol or hypertension.

Cognitive behaviour therapy (CBT) and counselling

As emotional problems such as depression and anxiety can contribute to increased risk of heart disease, it would appear CBT and counselling play an important role in the management of patients with heart disease and/or psychological symptoms to help reduce risk factors.³⁶

Stress

Stress has been identified as a causative factor in hypertension.³⁷ Stress is also known to precipitate cardiac events and is considered a more important marker of myocardial infarction than hypertension and diabetes. For example, viewing a stressful soccer match doubles the risk of an acute cardiovascular event such as risk of angina, myocardial infarction or arrhythmia.³⁸ A sudden emotional shock such as the loss of a loved one can cause symptoms of myocardial infarction even in patients with no clinically significant coronary disease³⁹, including in young people by triggering coronary vasospasm.⁴⁰

A review of the literature has found stress impacts adversely on health and on longevity and can increase the risk of stroke.^{41, 42} A study found that for women who are content with their lives at home and at work, atherosclerosis can actually regress, but progresses in those experiencing ongoing stress, independent of other CVD risk factors such as age, smoking, hypertension and HDL levels at baseline.⁴³ A Lancet review found a strong and consistent association between stress and CVD.⁴⁴

Siesta (afternoon nap)

Greek researchers demonstrated a daily siesta is protective towards CVD and coronary mortality according to a large scale cohort study of 23 681 individuals.⁵⁴ After excluding confounders, occasional napping reduced risk of coronary mortality by 12%, and systematic napping by up to 37%, particularly in working men, compared with non-nappers. However, a recent report warns that excessive daytime sleepiness is an independent risk factor for total and cardiovascular-related mortality in elderly individuals.⁵⁵

Sleep deprivation

Lack of sleep is being identified as a new risk factor for coronary artery disease, including calcification of the arteries. A US study of 500 healthy middle-aged men and women found that just 1 hour of extra sleep per night reduced the risk of calcification of the arteries (coronary artery calcification was measured by computed tomography) by an average of 33%.⁵⁶ This association was more pronounced in women. The study adjusted for all other risk factors such as age, sex and BMI. The researchers postulated that blood pressure drops during sleep, so insufficient or poor quality sleep may interfere with the decline in blood pressure, increasing the risk of CVD.

A Japanese study of hypertensive patients also found after adjusting for confounders, short sleep duration significantly increases the risk of CVD compared with normal sleep duration.⁵⁷ The researchers’ conclude that lack of sleep is an independent predictor of cardiovascular events.

Snoring and obstructive sleep apnoea (OSA)

OSA is a well-recognised risk factor for CVD and mortality, including nocturnal sudden cardiac death.^{58, 59} Sleep units are now well established in a number of hospitals, especially in developed countries, to help identify this problem and provide nocturnal oxygen inhalation therapy for those with confirmed sleep apnoea. Researchers found that sudden cardiac death occurred overnight significantly more in subjects with severe OSA (46%) than those without OSA (21%) or compared with sudden cardiac death victims in the general population (16%).⁶⁰ An observational cohort study of 110 subjects who underwent bilateral carotid and femoral artery ultrasounds to quantify atherosclerosis, demonstrated snoring is a significant independent risk factor for carotid (not femoral) artery atherosclerosis; the risk factor increasing with degree of severity of snoring.⁶¹

Chemicals

Diesel and/or carbon emissions

Exposure to air traffic pollution is known to increase the risk of CVD. In a double-blind, randomised, cross-over study of men with a history of myocardial infarction, brief exposure to dilute diesel exhaust caused exercise-induced ST-segment depression

significantly more profound during exposure to polluted air than in the control group who used clean air, and also reduced the acute release of endothelial tissue plasminogen activator, thereby increasing the thrombotic effect.⁹² These factors may explain the mechanism for increased CVD risk with combustion-derived air pollution.

Smoking

Smoking is clearly a major risk factor for arterial disease and large cohort studies demonstrate that smoking cessation is one of the most important factors that can modify risk of arterial disease. Various conventional approaches for smoking cessations are available.

Smoking can reduce all-cause mortality after smokers quit smoking. The Nurses Health Study, a prospective observational study of nearly 105 000 women over a 20-year period, found significant reduction in all-cause mortality in the first 5 years of smoking cessation by 13% and returned to the same level as non-smokers at 20 years compared with those who continued smoking during these periods.⁹³ Risk of death from vascular disease declined to non-smoking levels in 20 years. Smoking cessation can substantially improve health outcome, reduce CVD and reduce health care costs.⁹⁴

Exercise

A sedentary lifestyle may increase the risk for depression, hypertension, excess weight, abnormal lipids and CVD. It is well established that regular exercise for 30 minutes on most days can help prevent hypertension.⁹⁵ Exercise of this magnitude is important in maintaining an ideal weight and helping to normalise abnormal lipids.

A 15-year, prospective longitudinal study of up to 5000 men and women (aged 18–30 years), found walking throughout adulthood attenuates the long-term weight gain that occurs in most adults.⁹⁶

The National Heart Foundation and Medical Journal of Australia guidelines for clinically stable CVD recommend 30 minutes of low-moderate exercise most days which helps to reduce cardiovascular symptoms, augment physiological functioning, improve coronary risk profile and improve muscular fitness.⁹⁷ They also recommend for those who have suffered a recent cardiovascular event to have supervised exercise rehabilitation.

A study reporting on non-pharmacologic treatments for depression in patients with CHD reported that of the psychological therapies, such as cognitive behaviour therapy (CBT) and interpersonal therapy (IPT), aerobic exercise, St John’s wort, essential fatty acids, S–Adenosylmethionine (SAMe), acupuncture, and chromium picolinate, it was aerobic exercise that offered more promise to improve both mental and physical health due to its effect on cardiovascular risk factors and outcomes, however, future trials are warranted.⁹⁸

Yoga

Yoga has been recommended as efficacious in the primary and secondary prevention of ischaemic heart disease and post-myocardial infarction patient rehabilitation.⁹⁹ There are several studies that demonstrate yoga can reduce cardiovascular reactivity to stress, a factor that is strongly associated with cardiovascular risk.¹⁰⁰ Controlled studies have demonstrated that yoga can reduce blood pressure (see also Chapter 19, hypertension) and hence cardiovascular risk.^101–105

Tai chi

Tai chi promotes balance and flexibility, and can improve cardiovascular fitness and have substantial emotional benefits according to a control study.^{106, 107}

Qigong

Several randomised controlled trials have evaluated qigong interventions from multiple perspectives, specifically targeting older adults.¹⁰¹ In adults, particularly the aged, this form of physical activity can lead to significant improvements in physical functioning, mood, weight, and in the reduction of cardiovascular risk factors.¹⁰¹ Improvements in cardiovascular factors such as systolic and diastolic blood pressure, increased pre-ejection fraction and heart rate variability have been documented.^108–111

Musculoskeletal therapy

Some complementary and alternative physical therapies show promise in cardiac rehabilitation.¹¹² A recent study with stroke patients reported that single-modality exercises targeted at existing impairments do not optimally address the functional deficits of walking but did ameliorate the underlying impairments.¹¹³ Also the study reported that the underlying cardiovascular and musculoskeletal impairments were significantly modifiable years after stroke with targeted robust exercise. In another recent study it was reported that regular arm aerobic exercise lead to a marked reduction in systolic and diastolic blood pressures and an improvement in small artery compliance.¹¹⁴ The study further concluded that arm-cycling was a logical option for hypertensive patients who choose to support blood pressure control by sports despite having coxarthrosis, gonarthrosis, or intermittent claudication.

Acupuncture

An early report concluded that there were sufficient clinical studies in humans that demonstrate acupuncture can exert significant effects on the cardiovascular system and provide effective therapy for a variety of cardiovascular ailments.¹¹⁵ In a recent study of acupuncture and cardiac arrhythmias; the 8 eligible studies reviewed demonstrated that 87–100% of participants converted to normal sinus rhythm after acupuncture. Hence it was concluded that acupuncture seemed to be effective in treating several cardiac arrhythmias, but limited methodological quality of the studies necessitates better-controlled clinical trials to be performed.¹¹⁶

Diet

Dietary regimens that increase obesity and raise blood lipid levels and inflammatory markers (i.e. C–reactive protein) have an important role in increasing the risk for the development of chronic diseases such as myocardial infarction and stroke. It has been recently reported that vegetarians have a decreased prevalence of ischemic heart disease mortality that is probably due to lower total serum cholesterol levels, lower prevalence of obesity and higher consumption of antioxidant-type compounds in foods.¹¹⁷

Worldwide dietary patterns

Diet is a modifiable risk factor for CVD. The INTERHEART study involving 52 countries identified 3 major dietary patterns: Oriental (high intake of tofu, soy and other sauces), Western (high in fried foods, salty snacks, eggs, and meat), and prudent (high in fruit and vegetables).¹¹⁸ The study demonstrated an inverse association between the prudent pattern and acute myocardial infarction (AMI); the Western pattern showed a U–shaped association with AMI; the Oriental pattern demonstrated no relationship with AMI. The researchers concluded that the unhealthy dietary intake increases the risk of AMI globally and accounts for about 30% of the population-attributable risk.

The INTERGENE population study of 3452 participants (aged 25–74 years) identified dietary patterns associated with CVD risk factors, obesity and metabolic syndrome.¹¹⁹ Unhealthy food patterns were characterised by high consumption of energy-dense drinks and white bread, and low consumption of fruit and vegetables. Healthy food patterns was distinguished by more frequent consumption of high-fibre and low–fat foods and lower consumption of products rich in fat and sugar.

A recent Cochrane review of the literature also demonstrates dietary advice lowers prevalence and incidence of CVD.¹²⁰

The Seven Countries study demonstrated that population-related factors significantly affect the risk of CVD and that diet was directly related to the risk of developing coronary artery thrombosis that lead to heart attacks.¹²⁰ Dietary factors were far more significant than other risk factors, as variations in cholesterol and incidence of smoking in men from one country to another did not account for the differences seen in CVD. This study also demonstrated lower levels of many cancers, dementia and all-cause mortality in people who adhered closely to their traditional Mediterranean or Japanese diets.

Obesity

Weight management can significantly reduce cholesterol and other known risk factors, and slow progression of coronary artery disease that is associated with calcium deposition as with atherosclerotic plaque disease and coronary events in a cohort of patients with type 1 diabetes.¹²²

(See also the section on obesity earlier in this chapter.)

Mediterranean and Japanese diets

Vast quantities of research, including epidemiological studies, have demonstrated the value of the Mediterranean and Japanese diet in the prevention and management of CVD. Their dietary patterns feature high intakes of seafood, vegetables, nuts (e.g. walnuts) and seeds, cereals, fruit (usually for dessert) and legumes. The Mediterranean diet is also rich in olive oil intake. Both diets have some chicken, are low in red meat and dairy, and are mostly vegetarian and high in fish. The saturated fat content of egg and dairy products in the Mediterranean and Japanese diets (e.g. goats or sheep products such as yoghurt and cheeses, which forage on wild greens) differs from Western dairy intake in that they have higher content levels of omega-3 fatty acid (alpha linolenic acid).¹²³

Interestingly, a recent Japanese study found that high intake for fruit and vegetables was protective for CVD in women but not men.¹²⁴ High dietary soy may be cardio-protective according to a study of post–menopausal women by reducing blood pressure and lowering lipid levels.¹²⁵

A recent study that investigated the Mediterranean diet and the incidence of mortality from CHD and stroke in women reported that a greater adherence to the Mediterranean diet, as reflected by a higher alternate Mediterranean diet score, was associated with a lower risk of incident CHD and stroke in women.¹²⁶

Olive oil

A study of patients with stable CHD aimed to identify the effects of olive oil on cardiac risk factor blood parameters.¹²⁷ The placebo-controlled, cross-over, trial randomised patients with either raw daily dose of 50ml of virgin olive oil or refined olive oil over a total 6-week period and found reduction in the inflammatory markers interleukin-6 and C-reactive protein with virgin olive oil intervention compared with refined olive oil group, but no changes observed with glucose and lipid profile.

The polymeal

The polymeal, as opposed to the polypill, are the foods identified to be cardio-protective. The polymeal is far safer and more natural and can reduce the risk of CVD by more than 75% (see Table 10.1).¹²⁸ Taking the polymeal daily significantly increased total life expectancy far greater in men than in women.

Table 10.1 Effect of ingredients of polymeal in reducing risk of CVD

(Source: adapted from Franco et al. 2005)¹²⁸

A recent meta-analysis of 12 prospective cohort studies of over 1.5 million participants over a 3–18 year period affirms the health benefits of the Mediterranean diet.¹²⁹ Stricter adherence to the diet conferred significant cardiac protection, and led to further reductions in risk of all cause-mortality, death from CVD, as well as cancer and degenerative diseases compared with low adherence. Adherence to the Mediterranean diet can also significantly reduce the risk for type 2 diabetes.¹³⁰

The dietary approaches to stop hypertension (DASH) diet

The DASH diet is high in plant proteins, fruit and vegetables, with moderate amounts of low-fat dairy products and is low in animal proteins.

The DASH trial, which was an 11-week multi-centre feeding trial, tested the effects of dietary patterns on blood pressure. Participants (459) were divided into 3 groups; control, increased fruit and vegetables and a combination diet (rich in fruits, vegetable, low fat dairy and reduced saturated fat). In hypertensive subjects, the combination diet led to a mean reduction of blood pressure of –11.4 mmHg systolic and –5.5mmHg diastolic.¹³¹ It was also found to lower homocysteine.¹³²

Furthermore, the DASH diet also reduces the risk of heart disease and stroke among women independent of lowering hypertension.¹³³ An analysis of the Women’s Health Study involving over 88 000 women demonstrated adherence to the DASH diet significantly reduced the incidence of cardiac mortality or myocardial infarction by 24% and reduced the risk of stroke by 18% compared with a diet high in salt or fat during 24 years follow-up. It also reduced plasma levels of C-reactive protein and interleukin, both inflammatory markers.

High fibre diet

Total dietary fibre (cereal, fruit, and vegetable) is associated with a 14% reduction in the risk of all coronary events and a 27% decrease in the risk of coronary death.¹³⁴ Further research confirms its protective role towards CVD according to analysis of the Physicians Health Study I, that demonstrated consumption of wholegrain cereal at breakfast and high dietary fibre are associated with less prevalence of hypertension, lower risk of heart failure and reduced incidence of myocardial infarction.¹³⁵ Intakes of wholegrain fibre are inversely associated with progression of atherosclerosis, according to a study on post-menopausal women with coronary artery disease.¹³⁶ Oatmeal for breakfast also reduces the risk of CHD.¹³⁷

Dietary fibre also improves glycaemic control in diabetics, as well as lowering cholesterol/low-density lipoprotein LDL.

Low-fat diet

In the Mediterranean diet, Cardiovascular Risks and Gene Polymorphisms (Medi-RIVAGE) study from France, both the Mediterranean-type diet and the low-fat diet significantly reduced the risk factors for CVD equally for total cholesterol, triglycerides and insulinemia after adjustment for BMI during the 3-month intervention.¹³⁸

Vegetarian diet

A vegetarian diet has been reviewed for its beneficial and adverse effects in various medical conditions.¹³⁹ It was concluded in that study that the beneficial effects may be due to the diet (consisting of monounsaturated and polyunsaturated fatty acids, minerals, fibre, complex carbohydrates, antioxidant vitamins, flavanoids, folic acid and phytoestrogens) as well as the associated healthy lifestyle that vegetarians pursue. There were few adverse effects reported and these consisted of increased intestinal gas production and a small risk of vitamin B12 deficiency.

A more recent report conducted over a mean of 8.1 years suggested a dietary intervention that reduced total fat intake and increased intakes of vegetables, fruits and grains did not significantly reduce the risk of CHD, stroke, or CVD in post-menopausal women and achieved only modest effects on CVD risk factors, suggesting that more focused dietary and lifestyle interventions may be needed to improve risk factors and reduce CVD risk.¹⁴⁰

Fish and omega–3 polyunsaturated fatty acids

The benefits of eating just 1–2 servings of fish weekly can significantly reduce the risk of coronary death, which outweighs harm from contaminant exposure from mercury and dioxins from fish intake.¹⁴¹ Modest intake of fish consumption compared with eating fish only once weekly substantially reduced the risk of CHD amongst middle-aged persons.¹⁴² This prospective study of nearly 42 000 Japanese people demonstrated the more fish intake the lower the risk of CVD. The group with the highest fish intake, equivalent to 180g daily, reduced the CVD risk by 40%.

A number of cohort studies demonstrate that regular consumption of fish, even just 1–2 servings weekly, is associated with reduced risk of sudden death, cardiac arrest, heart failure and atrial fibrillation, compared with those who only eat fish once monthly.^{143, 144, 145}

Nuts

It is well recognised that nut consumption (e.g. 30–65g or 6–13 walnuts), which are high in monounsaturated fatty acids (MUFAs) and alpha-linolenic acid, is important for a healthy heart, improves vascular health and lowers lipid levels.^{146, 147} The Mediterranean diet usually consists of regular nut consumption. Of interest, pistachio nuts have a dose-response beneficial effect in reducing risk of CVD.¹⁴⁸ Just 2 doses of pistachios added to a low-fat diet can significantly reduce cholesterol levels in a dose-dependent manner. Pistachios have a high amount of phytosterol which may be contributing to the health benefits as well as lowering cholesterol levels. Another study demonstrated that sunflower seeds may also have the same benefit on CVD due to high phytosterol levels also.¹⁴⁹

Diet high in vitamin K

A diet high in vitamin K, particularly K2, is known to be protective for not only bones but also vascular health^{150, 151}

The Dutch Rotterdam study of over 4800 participants with no history of heart attacks found that a high dietary vitamin K2 intake in the upper third was associated with a 57% lower risk of dying from fatal cardiac disease and 52% reduction in severe aortic calcification compared with those in the lower third of total vitamin K2 intake.¹⁵² Furthermore, all-cause mortality reduced by 26%.

Vitamin K2 is important for activating matrix Gla-protein (MGP) — a strong inhibitor of vascular calcification that prevents build up of calcium in blood vessel walls.

Only 10% of dietary vitamin K intake is in the K2 form, the other 90% being the more common K1. Vitamin K2 is obtained mainly from the ‘good’ bacteria produced in the digestive tract and is also found in certain fermented foods. The ideal dietary source of K2 is natto, Japanese fermented soybeans.¹⁵⁴ vitamin K2 dietary sources also include butter, eggs, cow liver, fermented products and hard white cheese.

Salt/sodium restriction

Data from 2 randomised trials, TOHP I and TOHP II, involved a total of 3126 participants assessed over a 10–15 year period who were randomised to a sodium reduction intervention or control for 18 months (TOHP I) or 36-48 months (TOHP II).¹⁵⁵ The researchers found a significant reduction in risk of a cardiovascular event by up to 30% among those in the low-sodium diet intervention group compared with control group. The researchers concluded: ‘Sodium reduction, previously shown to lower blood pressure, may also reduce long-term risk of cardiovascular events’. ¹⁵⁴

A low-salt diet is also cardio-protective in normotensive patients, as well as effectively lowering blood pressure in hypertensives. A recent study of normotensive overweight and obese adults were randomised to low or standard diet groups.¹⁵⁵ Within 2 weeks the low-salt diet group (50nmol sodium per day) demonstrated 30% less brachial artery flow-mediated dilatation, lower systolic blood pressure and reduced 24 hour sodium excretion compared with the standard diet group. This study highlights the need to remove salt from many prepared foods and in the diet to prevent the onset of hypertension.

Cocoa and/or dark chocolate

Several studies have shown that cocoa can decrease blood pressure to a similar extent to that of pharmaceuticals.¹⁵⁶ New research suggests 1 serving of dark chocolate (20g; not milk chocolate) every 3 days significantly reduces the levels of the inflammatory marker C-reactive protein which may help to reduce inflammation, a known risk factor for many diseases, including CVD and cancer.¹⁵⁷ A 30-day trial demonstrated drinking a cup of cocoa daily can improve flow-mediated dilation and combat blood vessel dysfunction linked to diabetes.¹⁵⁸ Daily consumption of 46g of dark chocolate increased blood levels of flavonoid epicatechin and significantly improved arterial function in a group of healthy volunteers.¹⁵⁹

Alcohol

Whilst the cardio-protective properties of moderate alcohol consumption, compared with abstinence or heavy drinking, are widely recognised, this interesting study, a longitudinal-based cohort study, aimed to identify whether the benefits are experienced equally by all moderate drinkers.¹⁶⁰ The study found a significant benefit of moderate drinking was identified amongst those with poor health behaviours (little exercise, poor diet and smokers) compared with abstinence or heavy drinking. There was no additional benefit from alcohol amongst those with the healthiest behaviour profile (>3 hours vigorous exercise per week, daily fruit or vegetable consumption and non-smokers). The authors concluded the cardio-protective benefit from moderate alcohol drinking ‘does not apply equally to all drinkers, and this variability should be emphasised in public health messages’.¹⁶⁰ However, another large-scale US study of a cohort of 8867 men over 16 years found after adjusting for confounders, moderate levels of alcohol (5–30g per day) reduced the risk of myocardial infarction by up to 50%.¹⁶¹

Green and black tea

A large prospective cohort study involving 40 000 Japanese adults (aged 40–79 years) over an 11-year follow-up, after adjusting for demographics, lifestyle and medical risk factors, found that green tea consumption was associated with significant reduction of all-cause and cardiac mortality, but not for cancer mortality. The inverse association was particularly in those drinking more than 5 cups of tea daily, compared with less than one, and was stronger in women than men.¹⁶⁵

Similarly, drinking at least 3–4 cups of black tea a day was also protective for cardiac disease and reduced the risk of developing MI, according to a review of the literature.¹⁶⁵

Coffee and energy caffeinated beverages

There is increasing consumption of energy caffeinated drinks by young people. A published case report described an otherwise healthy 28-year old man who developed a cardiac arrest due to an ischaemic event from vasoconstriction, even though angiogram did not show significant coronary lesions, and arrhythmia triggered by the excessive ingestion of caffeine- and taurine-containing energy drinks and strenuous activity.¹⁶⁶ Caffeine before exercise might be more significant as it may impede blood flow during exercise. According to a study of young regular coffee drinkers, just 200mg caffeine dose (equivalent to 2 cups of coffee daily), significantly reduces exercise-induced myocardial flow reserve and this effect is more pronounced at high altitude.¹⁶⁷

A large US study of over 125 000 adults found even drinking in excess of 6 cups of coffee (mostly filtered coffee) per day did not increase risk of CHD, even in those with type 2 diabetes or who were obese; however, they were more likely to take aspirin, possibly for caffeine withdrawal symptoms!¹⁶⁸

A 3.5 year follow–up study of over 11 000 men who had had a myocardial infarction in the previous 3 months, demonstrated that moderate caffeine consumption (2–4 cups daily) did not increase cardiovascular events. ¹⁶⁹

Pomegranate juice

An RCT demonstrated drinking daily pomegranate juice for 3 months compared with placebo can improve myocardial perfusion in patients with CHD and ischaemic disease.¹⁷⁰ Pomegranate can also improve serum lipids.

Phytonutrient juice powder

A recent pilot study suggests that a phytonutrient concentrate consisting primarily of fruits, vegetables and berries — including acerola cherry, apple, beet, bilberry, blackberry, black currant, blueberry, broccoli, cabbage, carrot, cranberry, Concord grape, elderberry, kale, orange, papaya, parsley, peach, pineapple, raspberry, red currant, spinach and tomato — induced several favourable modifications of markers of vascular health in the study participants. The study supported the concept that plant nutrients are important components of a heart-healthy diet.¹⁷¹

Antioxidants

A US cross-sectional study assessed users of a broad range of daily nutritional, herbal and dietary supplements.¹⁷² After adjustment for age, gender, income, education and BMI, supplement use was associated with optimal levels of chronic disease biomarkers (serum homocysteine, C-reactive protein) and high-density lipoprotein cholesterol and triglycerides, less likely to have sub-optimal blood nutrient levels, elevated blood pressure, high BMI and diabetes compared with non-users or multivitamin/mineral users alone.

A trial of 13 017 French adults (7876 women aged 35–60 years and 5141 men aged 45–60 years) randomised to either a single daily capsule of antioxidants (120mg of ascorbic acid, 30mg of vitamin E, 6mg of beta-carotene, 100mcg of selenium and 20mg of zinc) or a placebo over a 7.5 year period. The study found the antioxidant supplement reduced the risk of cancer and all-cause mortality in men, but not in women.¹⁷³ The researchers postulated that men are more likely to have lower baseline status of certain antioxidants, especially of beta-carotene.

Vitamins E and C

There is increasing biological plausibility for the use of vitamin supplements for the prevention of CVD. Oxidised LDL cholesterol attracts and interacts with monocytes, macrophages and platelets to promote atherogenesis and also causes endothelial necrosis plus interferes with vaso-relaxation. vitamins E and C have been shown to inhibit LDL oxidation and vitamin E reduces endothelial monocyte adhesion, as well as inhibiting platelet activation.^174–176 Angiographic and ultrasonographic studies in humans suggest that vitamin E also inhibits the progression of atherosclerosis.^{8, 9, 177} Often researchers do not distinguish between the synthetic and natural forms of vitamin E which have different structures and functions. Studies in general that utilise natural vitamin E and at doses of 500IU or above have shown a benefit.¹⁷⁸ Whereas, studies that employed a lower dose or the synthetic form of the vitamin were found to be ineffective.¹¹ There is a known synergy between vitamin E and vitamin C plus selenium that allows for a maximum benefit.

Vitamin E is synergistic also with aspirin as they are both cyclooxygenase inhibitors which significantly increases the efficacy of aspirin therapy.¹⁷⁹ Unfortunately, there are no primary prevention studies that have evaluated the role of natural vitamin E. Vitamin C, in addition to regenerating the antioxidant properties of vitamin E, has an anti-inflammatory action which is thought to be important in the prevention of arterial disease.¹⁸⁰

According to the Physician’s Health Study II, a double-blind, placebo-controlled trial of high doses of synthetic vitamin E (400IU 2nd daily) with vitamin C (500mg daily), or provided alone, compared with placebo over an 8-year period was not cardio-protective and did not reduce total mortality.¹⁸¹ It was also concerning that the vitamin E treatment group had a marginally significant increased risk of hemorrhagic stroke, which is plausible as vitamin E is known to prolong bleeding times. It is likely the benefits of vitamin E witnessed in other trials are found with the natural forms (not synthetic).

Findings from the Women’s Antioxidant Cardiovascular study of 1450 women also demonstrated no overall benefit of either ascorbic acid (500mg/d), vitamin E (600IU every other day) and beta-carotene (50mg every other day) for CVD, although there was a marginally significant reduction in the vitamin E group in women with prior history of CVD and those randomised to both active ascorbic acid and vitamin E experienced fewer strokes.¹⁸² There are concerns with the use of synthetic vitamin E.

Vitamin B