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We Are What We Eat: Women and Diet for Cardiovascular Health

Albert, Nancy M. PhD, RN, CCNS, CCRN, CNA

The Journal of Cardiovascular Nursing: November-December 2005 - Volume 20 - Issue 6 - p 451-460
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In women, cardiovascular disease is highly prevalent and is costly in terms of mortality and morbidity. Healthcare providers should educate women about initiating and maintaining a cardiovascular-healthy diet as a cornerstone of primary and secondary prevention. The difficulty comes in determining the correct messaging regarding diet components. Women should routinely consume a diet known to prevent coronary heart disease, stroke, and other cardiovascular risk factors. Essential aspects of good nutrition for women include diets rich in fiber, whole grains, fresh fruits, vegetables, fish, nuts, antioxidants, minerals, vegetable protein, marine and plant omega-3 fatty acids, and vitamins of the B group. Some foods known to provide cardiac protection in women, such as potatoes and citrus fruit juices, may not be cardioprotective in men. Thus, it is important to continue research efforts in women to determine the best diet for cardiovascular health.

Nancy M. Albert, PhD, RN, CCNS, CCRN, CNA Director, Nursing Research, Division of Nursing; Clinical Nurse Specialist, George M. and Linda H. Kaufman Center for Heart Failure, The Cleveland Clinic Foundation, Cleveland, OH.

Corresponding author Nancy M. Albert, PhD, RN, CCNS, CCRN, CNA, The Cleveland Clinic Foundation, 9500 Euclid Avenue, M-14, Cleveland, OH 44195 (e-mail: albertn@ccf.org).

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Introduction

In women, cardiovascular disease (CVD) is the leading cause of death in the United States and in most other countries.1 In the United States alone, over 500,000 women will die each year, translating into one death every minute.1 Cardiovascular (CV) deaths in women have remained constant, whereas men have had a decline in recent years. Of all causes of CV death in women, coronary heart disease accounts for over 250,000 cases annually.2 Women develop coronary heart disease about 10 years after men and are about 20 years older than their male counterparts when they develop events such as myocardial infarction and sudden cardiac death.2 After the myocardial infarction event, female survivors are more likely to die while hospitalized and within 1 and 5 years of the initial event.2 In addition, after coronary artery bypass graft surgery, women are twice as likely to have a fatal event as compared to men, and younger women are at even higher risk of mortality.2 Although sudden cardiac death is more common in men than in women, coronary heart disease risk factors predict risk for sudden cardiac death in women; specifically, smoking, hypertension, and diabetes.3 Sudden cardiac death is usually an arrhythmic death in women; therefore, the incidence of sudden cardiac death may be reduced by strategies that prevent atherosclerosis or ventricular arrhythmias.3

In addition to gender differences in CV survival, gender and ethnic differences also influence morbidity. Racial and ethnic minorities are at a greater risk for coronary heart disease than European American women.1 Women are more likely to have a recurrent myocardial infarction within 6 years of the initial event.2 Women who experience acute coronary syndrome may have atypical symptoms and pain in abnormal pain locations.4 Perceptual differences of an acute coronary experience in men and women may affect how cardiac symptoms are interpreted and how information is conveyed to healthcare providers.5 After a percutaneous coronary intervention, women have successful outcomes but experience more postprocedure anginal pain than men, leading to limitation in activities and quality of life.2

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Why Focus on Diet?

In the United States, over 60% of adult women are overweight.6 Elevated body mass index and obesity are associated with dyslipidemia, diabetes, and hypertension;7 all of which are risk factors for CVD in women.8 Weight loss has been an ongoing recommendation for patients with excess body weight for years. Researchers have learned more about the connection between fat distribution in women and CV risk. Women generally present with gluteofemoral obesity, whereas men are more likely to have generalized abdominal obesity.9 While fat in itself has been thought to be bad, intra-abdominal fat found on centrally obese individuals is carried viscerally, rather than as subcutaneous fat. In women, visceral to subcutaneous fat correlates with waist-to-hip ratio but not with body mass index.9 Increased visceral fat is associated with type 2 diabetes, increased glucose levels, increased plasma triglyceride levels, and decreased high-density lipoprotein (HDL) cholesterol.9 Thus, adiposity in itself might not be the culprit in CV risk in women; rather, those that uncharacteristically accumulate more visceral fat and present with metabolic abnormalities may be at higher CV risk. A more targeted area for primary and secondary CV prevention may be in targeting CV risk factors characteristic of metabolic syndrome (hypertension, dyslipidemia [high plasma triglyceride and low HDL levels], insulin resistance, and abdominal obesity).

In 1993, the National Cholesterol Education Program (NCEP) Expert panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel II) issued nonpharmacologic therapy recommendations that focused on a combination of physical activity and dietary therapy.8 Diet recommendations were aimed at reducing intake of saturated fatty acids and cholesterol and promoting weight loss when overweight by eliminating excess total calories.8 In 1999, a meta-analysis was conducted to assess if the Adult Treatment Panel II guidelines were still current.10 Investigators concluded that the Adult Treatment Panel II goals were on target but that lipid-lowering therapy should be aggressively applied in patients with diabetes. In 2001, the NCEP published Adult Treatment Panel III guidelines. Emphasis was placed on full fasting lipid profile screening, increased thresholds for low HDL cholesterol, inclusion of low HDL cholesterol as a marker for metabolic syndrome, and recommendations for increasing HDL cholesterol.11

Women with CVD have higher rates of diabetes compared to men.4 In a large ischemia syndrome evaluation study in women (WISE), metabolic syndrome, but not obesity, predicted future CV events.7 Even before menopause and the appearance of metabolic syndrome, excess central adiposity and a proinflammatory milieu (related to insulin resistance) contributed to atherosclerosis.12 It is believed that microvascular processes played a larger role in coronary artery disease in women than in men because women had smaller arteries, more ventricular remodeling, and an unexplained higher cardiac event rate. This association was especially strong in young women (43 to 72 years) who developed coronary artery disease.12 Thus, researchers concluded that control of modifiable risk factors in both normal and overweight women to prevent the onset of metabolic syndrome was an important goal in preventing CVD.

Compared to men, women are more likely to have hypertension as a risk factor for CVD.4 In women with CVD, hypertension leads to subsequent CVD events. In a prospective study of 5,218 middle-aged and older female health professionals (mean age was 62 years) with CVD, systolic blood pressure was a strong predictor of CVD events (nonfatal myocardial infarction, stroke, coronary artery bypass graft or percutaneous angiography procedure, or CVD death).13 For every 10 mm Hg increase in systolic blood pressure, there was a 9% increase in secondary CVD events. Importantly, antihypertensive medications did not modify the relationship between systolic blood pressure and CVD events.13 Thus, systolic blood pressure is an important independent risk factor for CVD morbidity and mortality in both primary and secondary prevention that requires control.

A person's diet can affect lipids, systolic blood pressure, and prevalence of metabolic syndrome. In a recently published guide of CVD prevention in women, 4 of the 8 clinical recommendations for lifestyle modifications were diet related. Specific diet recommendations were consuming a heart-healthy diet, weight maintenance/reduction, omega-3 fatty-acid supplementation, and folic acid supplementation.1

Why is diet so important to women's CV health? To answer this question, a summary of results of studies that included diet modification as an aspect of lifestyle modification will be reviewed. Research reports highlight the benefits of specific food types compared to others and the benefits of diet themes: a low-fat diet, a low-carbohydrate/high-fat diet, and the Mediterranean diet to maintain CV health. The results of studies that used specific food types and specific diets will be reviewed and discussed to provide evidence for promoting specific diet recommendations. Finally, suggestions will be provided to promote CV health through diet. If the saying "we are what we eat" is indeed true, then promotion of a CV-healthy diet can help both overweight and normal weight women to have enhanced protection from both primary and secondary CV events that are not only life limiting but also affect quality of life.

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Lifestyle Modification by Diet

General Findings

Many prospective and descriptive studies have reported the benefits of diet on CV risks. These studies focused on multiple CV outcome endpoints, such as cardiovascular death,14,15 mortality from coronary artery disease,16,17 sudden cardiac death,18,19 anginal frequency and severity after coronary artery bypass graft or percutaneous coronary intervention,20,21 blood pressure reduction,22,23 risk of stroke,24 cholesterol reduction,25 lowered heart rates,26 prevalence of metabolic syndrome,27 type 2 diabetes,28 and multiple endpoints that included weight, blood pressure, serum glucose, serum lipoprotein levels, and diet compliance.29,30 Specific diet and nutrient recommendations varied widely by the patient population studied and the specific CV risk factor or other outcome variable of interest. Diets and nutrients studied were the Ornish diet; Mediterranean (Lyon) diet; vegetarian diet with emphasis on plant sterols, almonds, soy protein, and viscous fiber; prepared meal plans by Campbell Food Company; fish; DASH diet; long-chain omega-3 polyunsaturated fatty acids found in fish and plants; folic acid, vitamins B12, and vitamin B6 to lower homocysteine level; and nut consumption.

Although each study provides information that can be applied in practice, there are some caveats. All reports emphasized the importance of diet in the prevention or treatment of CV risk factors/diseases; however, some studies were descriptive designs. In these, results were hypothesis generating rather than definitive in providing specific recommendations. Some studies had nondiet lifestyle modification interventions and did not report outcomes by intervention type. In studies that did report the influence of diet or nutrients on outcomes, the distribution of diet and other interventions and relative risk for outcome variables were not always available, making it difficult to draw conclusions about the importance of diet findings in relation to nondiet interventions. Some studies were conducted exclusively in men. Other studies that included women did not include subgroup analysis based on gender or the study was not designed or powered to specifically determine differences by gender. In studies that included women and reported results by gender, women benefited similarly to men. None of the reports were replication studies and no studies compared 2 specific CV-healthy diets; thus, it is difficult to determine a diet preference and to make recommendations that could provide the best strategy for improving CV health.

Of the diet studies on CV risk sited above, 3 randomized trials deserve further discussion. Two studies compared diet and other lifestyle modifications to drug therapy. Metformin was compared to intensive lifestyle modification (healthy low-calorie, low-fat diet to reduce weight by 7% and moderate intensity physical activity for at least 150 minutes per week) and placebo in patients at high risk for type 2 diabetes.28 Intensive lifestyle modification was more effective than metformin in reducing the incidence of diabetes in both men and women during the mean follow-up period of 32 months. Lifestyle modification led to a much larger decrease in weight and greater physical activity than placebo or metformin,28 but the researchers did not report the influence of diet changes as compared to physical activity in influencing outcomes. In a study to determine the best treatment for hypercholesterolemia, 3 intervention arms were compared: (a) a diet low in saturated fat, (b) a low-fat diet plus lovastatin 20 mg/d, or (c) a diet portfolio that was high in plant sterols, soy protein, viscous fibers, and almonds.25 Both the lovastatin and diet portfolio groups led to reductions in low-density lipoprotein (LDL) cholesterol and C-reactive protein; however, the low saturated fat diet only group failed to derive benefit.25 The results of these two studies provided evidence that diets aimed at reducing type 2 diabetes and hypercholesterolemia are as or more effective than drugs in CV risk reduction. These results heighten our awareness that diet modification, alone or in combination with other lifestyle or drug therapies, is beneficial in women and should be a routine part of patient education and adherence to treatment plan monitoring.

In a trial that studied blood pressure control in patients who were not on antihypertensive agents, 3 intervention arms were compared: (a) advice only, (b) established recommendations for blood pressure control (weight loss, moderate intense physical activity, 100 mEq sodium or less per day, limited intake of alcohol per day), and (c) established recommendations plus the DASH diet (increased consumption of fruits and vegetables, low-fat dairy products, and reduced intake of saturated fats and total fat).22 Both the established recommendations groups reduced weight, improved fitness, and lowered sodium intake. Participants in the DASH diet group had a nonsignificant reduction in systolic blood pressure at 6 months compared to the other established recommendation group, and the prevalence of hypertension at 6 months was significantly lower in the DASH group compared to the other groups.22 These results provide further evidence that diet interventions targeted to reducing the prevalence of hypertension are effective.

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Low-Carbohydrate, High-Fat Versus Low-Fat Diets

Two recent reports of randomized trials provide further evidence in the growing literature of short-term safety in following a low-carbohydrate, high-fat diet as opposed to a conventional diet that focuses on a reduction of fat and cholesterol. Low-carbohydrate diets are controversial because they promote consumption of animal protein that is two to two and a half times higher than American Heart Association guidelines and low amounts of carbohydrates.31 Although these diets do not push caloric restriction, they cause a state of ketosis, which not only leads to a high use of fat stores for energy, but also is thought to suppress the appetite. Caloric deprivation is inevitable and may lead to dehydration, malnutrition, and deficiency in fiber and phytochemicals. Weight loss occurs from both caloric restriction and loss of body water.31 Researchers have advocated the use of dietary supplements when consuming a low-carbohydrate diet to avoid deficiency disorders such as flax seed oil, borage seed oil, fish oil, vitamin E, and fiber. In addition, high protein intake has been associated with renal insufficiency from a decline in glomerular filtration rate in women with mild renal insufficiency31 (that is common in the elderly as a normal part of aging). Thus, many questions remain regarding the long-term benefits and risks of a low-carbohydrate, high-fat diet.

Yancy et al32 compared a low-carbohydrate, high-fat diet with a low-fat diet in 120 overweight, hyperlipidemic participants for a 6-month period. More people in the low-carbohydrate diet completed the study. In addition, the low-carbohydrate group lost more weight, had greater decreases in serum triglyceride levels, and greater increases in HDL cholesterol levels. Losses in fat mass and fat-free mass, and decreases in LDL levels were similar between groups. There were more minor adverse effects in the low-carbohydrate group compared to the low-fat group. These included constipation, headache, halitosis, muscle cramps, diarrhea, general weakness, and rash. The majority of participants in each group were women. Of note, 25% of low-carbohydrate diet participants and 43% of low-fat diet participants did not complete the study for a variety of reasons.32

Stem et al33 compared a low-carbohydrate diet with a diet that restricted caloric intake by 500 calories per day and decreased fat consumption to less than 30% of calories from fat in 132 very obese adults for a 1-year period. Diabetes (insulin dependent and those on oral medications) or metabolic syndrome was prevalent in 83% of participants. Weight loss was nonsignificantly greater in the low-carbohydrate diet group; however, serum triglyceride levels decreased more and HDL cholesterol decreased less than in the conventional diet group. In addition, hemoglobin A1c levels improved more in the low-carbohydrate group. The majority of participants in this study were male; less than 20% of participants were women. Of note, 34% of participants dropped out of the study and there was suboptimal diet adherence in participants who maintained enrollment.33

Both studies had a small sample size and researchers failed to report results by gender, so it is unknown if gender influenced results. Studies had similar overall results although each had a high population of one gender compared to the other. The high dropout rate in both studies emphasized the difficulty of adhering to a weight loss plan and lack of adherence when preconceived perception of weight loss was greater than actual weight loss. In addition, a fast weight loss does not guarantee continued weight loss at 1 year. In a study of Stem et al, there was a nonsignificant weight loss at 1 year. These findings provided evidence that randomized trials for longer than 1 year are needed to determine the long-term effects of weight, lipid profile, and adverse effects of a low-carbohydrate diet over time.

Three editorials followed the publication of these research reports. Physicians, 2 from cardiovascular medicine and 1 nutrition specialist, had opposing views concerning the salutary effect of low-carbohydrate, high-fat diets on obesity, diabetes, hypercholesterolemia, and metabolic syndrome over time. Two physicians had concerns about low-carbohydrate diets that centered around their lack of nutritional requirements for vitamins, minerals, and dietary fiber;31 unlimited servings of fat and protein from beef, sausage, and butter; and the variation in weight loss among participants.34 Other dietary strategies were offered as more beneficial for CV risk reduction and these physicians encouraged a focus on finding ways to eat that can be maintained without a yo-yo weight effect.31,34 The third editorialist had a different perspective about promotion of a low-carbohydrate diet. His review focused on the unintended and unanticipated negative effects of a low-fat diet on the current epidemic of obesity, abnormal lipid patterns, type 2 diabetes, and the metabolic syndrome and the potential influence of a low-carbohydrate diet in overturning these bad outcomes.35 Viewpoints spanned the spectrum from not recommending a low-carbohydrate diet as a part of a long-term care plan for weight maintenance,31 to believing that a low-carbohydrate diet should be experimented with in overweight patients,34 to a perspective that the low-fat diet may have a favorable impact on CV outcomes and should not be summarily rejected.35

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Diet Studies in Women

The most prominent studies of diet, lifestyle, and CVD have come from the Nurses' Health Study, a longitudinal study of female registered nurses that began in 1976. Participants completed mailed questionnaires about lifestyle and medical history every 2 years. Diet was first assessed in 1980. Each of the reported studies below contains over 50,000 women and provides data from a long follow-up period, generally over 10 years.

The Nurses' Health Study cohort was the source of data in a primary prevention study of coronary heart disease. Diet and lifestyle were studied during 14 years of follow-up from 1980 to 1994.36 In 84,129 women who participated, those with a very low risk of coronary heart disease had a diet with the following 6 components: low in trans fat and glycemic load; high in cereal fiber, marine omega-3 fatty acids, and folate; and a high ratio of polyunsaturated to saturated fat. There was a positive association in relative risk of coronary events (nonfatal myocardial infarction or death from coronary heart disease) in nurses as total diet scores (calculated by summing the 6 components) deviated from the reference quintile (representing nurses with diets in the low-risk profile as described above). In addition, each of the 6 components of the dietary score was independently significantly associated with risk for coronary events over time.36 Overall, only 20% of nurses had diets consistent with the highest dietary score that represented the lowest risk for coronary events. Nurses with dietary scores in the lowest quintile had a relative risk of coronary events nearly twice as large as those with the highest dietary scores. The only factor more powerful than diet for relative risk of coronary events in the Nurses' Health Study was smoking.36

In a prospective cohort design, 84,251 eligible women from the Nurses' Health Study and 42,148 eligible men from the Health Professionals' Follow-Up Study (male health professionals including dentists, veterinarians, pharmacists, and others were recruited in 1986) were followed for vegetable and fruit consumption and its relationship on nonfatal myocardial infarction or fatal coronary heart disease.37 Results were reported by gender. In women, median total fruit and vegetable intake was 5.8 servings per day. For each 1-serving per day increase in intake, the relative risk reduction of coronary heart disease was 13%. After adjustment for smoking and other risk factors, the relative risk reduction was 3% for every 1-serving per day increase in fruit and vegetable intake. In analyses adjusted for nondietary risk factors, women in the top quintile of fruit and vegetable intake had a 20% lower risk for coronary heart disease than those in the worst quintile. All fruits, citrus fruit juice, and citrus fruits conferred benefit in women; for each 1-serving per day increase in intake, the relative risk reduction for coronary heart disease was 5%, 5%, and 7%, respectively. Of all fruits and vegetables consumed, 3 had the greatest inverse relationship to risk. Per each 1-serving per day increase in intake in green leafy vegetables, cruciferous vegetables, and potatoes, risk for coronary heart disease in women decreased by 30%, 24%, and 22%, respectively. Only intake of legumes was positively associated with coronary heart disease in women. Of note, potatoes, legumes, and citrus fruit juice were all positively associated with coronary heart disease in men.37

The protective benefits of fruits and vegetables can be due to many mechanisms; antioxidant vitamins, fiber, folate, and other minerals.37 The overall benefits of fruit and vegetable intake in women was equal to and somewhat less than the benefit achieved with statin use, because statins provide approximately a 30% risk reduction in coronary heart disease. Thus, consumption of fruits and vegetables, especially green leafy and cruciferous vegetables and potatoes, should complement other risk reduction efforts.37 Finally, it cannot be assumed that fruits and vegetables that are non-CV protective in men are also non-CV protective in women. In this epidemiologic study, potatoes and citrus fruit juice conferred benefit in women. Further studies will be needed to confirm these findings.

To assess whether higher consumption of omega-3 fatty acids was associated with lower risk of nonfatal myocardial infarction or fatal coronary heart disease in women, 84,688 females enrolled in the Nurses' Health Study who were free from cancer and completed questionnaires at 6 time points between 1980 and 1994 were included.38 Average fish intake was grouped into quintiles that ranged from less than 1 time per month to 5 or more times per week. Compared to the lowest quintile of fish consumption, the relative risk of coronary heart disease decreased by 20% to 36% as more fish was consumed. These results were consistent for age-adjusted and multivariate analyses for total coronary heart disease, nonfatal myocardial infarction, and fatal coronary heart disease (P for trends <.001 to.10). In the highest quintile of fish consumption, even after risk was adjusted for multiple variables, relative risk reduction continued to range from 33% to 45%. Data were also analyzed based on fish known to be high in omega-3 fatty acids. Results were similar to fish consumption: those who were in the highest quintile for omega-3 fatty acid intake had a 37% to 58% risk reduction for coronary heart outcomes, even after multivariate analyses. Data were stratified based on aspirin users (at least once per week) and nonusers. The inverse relationship for both fish and omega-3 fatty acid intake was stronger in women who did not use aspirin regularly; however, the relative risk reductions in coronary heart disease in both groups remained strong as consumption increased. The ratio of omega-6 (linolenic) to omega-3 (the sum of α-linolenic acid and fish oil) fatty acid intake was also analyzed. Results showed that omega-3 fatty acids were associated with a significantly lower risk of coronary heart disease in both low and high ratio omega-6/omega-3 groups.38 Thus, even after repeated-measures analysis and adjustment for confounding dietary variables, results suggest that fish consumption is cardioprotective, especially against fatal coronary heart disease.38

A 12-year follow-up study of 75,521 Nurses' Health Study women without diabetes, coronary heart disease, stroke, or other CVD was conducted to determine the incidence of ischemic stroke based on consumption of whole grains.39 Whole grain consumption was separated into quintiles and included dark bread, whole grain breakfast cereal, popcorn, cooked oatmeal, wheat germ, brown rice, bran, and other grains. Researchers also assessed consumption of refined grain foods (sweet rolls, cakes/desserts, white bread, pasta, muffins or biscuits, white rice, pancakes, waffles, pizza, and refined grain breakfast cereal) on risk for ischemic stroke. The age-adjusted relative risk of ischemic stroke decreased from lowest (referent) to highest quintile of whole grain consumption (P =.003). Compared to the lowest quintile, risk reductions ranged from 32% to 51%. The inverse association remained similar after adjustment for CVD risk factors, including saturated fat and trans-fatty acid intake, and also after subgroup analysis by nonsmokers, nondrinkers of alcohol, no vigorous physical activity, and non-postmenopausal hormone use (P for trends <.006 to.22). Refined grain foods did not significantly reduce the incidence of ischemic stroke.39 Thus, high intake of whole grain foods confers CV protection from ischemic stroke, even in women with known CV risk factors.

All 3 studies had similar limitations and positive points. Measurement error was inevitable as data were collected through self-administered questionnaires. Day-to-day variation in food and nutrient intake as well as in other lifestyle behaviors could affect results. There may be other confounding factors that were not analyzed in each study. Results cannot be generalized to all women because female nurses were the only group studied. However, in all studies, data were collected prospectively at prespecified points, before the outcome variables of interest occurred. In addition, all 3 studies were consistent in that, as fruit and vegetables, fish, omega-3 fatty acids, and whole grain consumption increased, there was a positive inverse relationship in CV risk. In addition, the fish consumption report provided specific evidence in women that was consistent with published reports of fish consumption in men.15,18,24

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Suggestions for Optimizing Diet for CV Health in Women

Because food sustenance is life sustaining and must be regularly carried out, it can be considered the cornerstone of CVD prevention and treatment efforts. In women, diets rich in fiber from fruits and cereal can reduce risk of coronary heart and ischemic stroke events. Fresh fruits, vegetables, fish, and whole grains should be sought over refined grains and foods high in fat content because there is abundant evidence of their beneficial effects. The trendy low-carbohydrate diet is not easy to maintain over time and prevents consumption of high-quality carbohydrates that are beneficial. Eating foods based on NCEP Adult Treatment Panel III guidelines can lead to achievement of reduced LDL and elevated HDL cholesterol levels known to be associated with CV risk reduction, as seen in the Heart Protection Study.40

Of all diets reviewed, a dietary pattern characteristic of the Mediterranean (Lyon) style diet seems to come closest to promoting a well-balanced diet that is known to confer CV risk reduction. This diet contains a large intake of fibers, antioxidants, minerals, vegetable protein, marine and plant omega-3 fatty acids, and vitamins of the B group. In the Lyon Heart Study, emphasis was placed on more bread, root vegetables, green vegetables, beans, nuts, and seeds. It promoted less beef, lamb, and pork. Red meat was replaced by more poultry. No day was complete without fruit, and butter and cream were replaced with margarine high in α-linolenic acid. Olive oil was an important source of fat for salads and food preparation. Dairy products, fish, and poultry were consumed in low to moderate amounts. Eggs were consumed from zero to 4 times per week and wine was consumed with meals.41 In the Lyon Heart Study, 1,947 total calories were consumed per day. Percent of total calories from fat and protein was 30.4% and 16.2%, respectively. Saturated, monounsaturated, and polyunsaturated fat made up 8%, 13%, and 5% of total calories, respectively. Omega-9 (oleic acid), omega-6 (linoleic acid), and omega-3 (linolenic acid) fatty acids accounted for 12.9%, 3.6%, and 0.84% of total calories. Alcohol accounted for 5.8% of total calories through red wine consumption. Daily total fiber content was 18.6 g and cholesterol consumption was 203 mg/d.41Table 1 provides specific diet suggestions that are protective to CV health.

TABLE 1

TABLE 1

TABLE 1

TABLE 1

There are 2 steps that can facilitate a CV-healthy diet. First, do not assume women have diet facts or understand dietary literature. In a study of cardiac patient's nutrition knowledge, only 30% of 606 patients reported that they fully understood their diet literature. When questioned about their diet knowledge, scores did not exceed chance levels.42 Thus, nutrition counseling must be given higher importance. Women should be referred to dieticians on a routine basis and healthcare providers must be cognizant of the need to question women about their knowledge of a CV-healthy diet so that assumptions regarding education are not made. All women should be educated about a CV-healthy diet, regardless of current risk, as CVD still claims more lives than any other medical condition.

Second, reinforcing diet principles is an important first step in achieving lifestyle change and adherence; however, education is not enough because increased knowledge does not always translate into behaviors.43 This is especially true for diet behaviors, as many women may be free of CVD or have asymptomatic CVD that does not provide a heightened sense of threat and danger of CV risk. Therefore, diet education must be considered only one aspect of a multidimensional program geared toward outcome achievement. For hospitalized patients, discussion of a CV-healthy diet should begin while hospitalized, when the patient is focused on their CV condition and has an implicit sense that there is danger associated with their condition. Emphasis should be placed on the need to continue a CV-healthy diet after discharge, even when asymptomatic. Monitoring, follow-up, and further education should continue in the outpatient setting.

Oftentimes, adherence is more easily achieved when a person (a) has confidence that they can carry out diet behaviors correctly, (b) has an opportunity to demonstrate new skills, and (c) can see the results of their behaviors. Consider developing or utilizing existing programs that help to maintain diet adherence. These can include support groups, cooking classes, telephone monitoring, ongoing written materials that enhance knowledge and skills, and follow-up outpatient monitoring. Communicate serum lipid and other pertinent labwork information and provide cause and effect information so patients can clearly see that their diet behaviors are facilitating or hindering their serum lipid and other test results. Provide written diet principles to patients so that they can refer to instructions, as needed. Also, provide advice about eating away from home, so that desired behaviors can be encouraged at all meals, not just those eaten in the home.

As healthcare providers, do not assume educators know diet principles and can speak about them without referring to written resources. Use a simple pocket card to spell out examples of refined versus whole grains, omega-3 fatty acids, and other foods that should be encouraged. Include foods rich in vitamin B6, vitamin B12, and other nutrients of importance. Ensure that nurses understand important diet principles and can communicate these principles effectively.

A body mass index of less than 25 kg/m2 is the standard cutoff point for overweight.36 In women, the risk of coronary heart disease is lower when the body mass index is 18.5 to 21 kg/m2, rather than in the 23 to 24.9 kg/m2 range.44 Overweight and obese adult women in the Framingham Heart Study had reduced survival when compared to women with normal weights.45 The mortality hazard ratios were consistently worse in the overweight and obese groups even after adjustment for hypertension, diabetes, physical activity, and education information at baseline examination.45 Ultimately, when discussing an optimal diet, correlation should be made to lowering weight to a normal level for height so that the risk of coronary heart disease and associated morbidity and mortality is reduced.

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Conclusion

Unfortunately, CV diet advice is confusing. There are many diets that claim to have benefits in maintaining general health and fitness, reducing obesity, and in reducing CV risk. Those wishing to entertain the latest fad diet for weight loss may ignore important principles of a CV-healthy diet, especially when the general media promotes the fad diet as being heart-healthy. Specific diets have been developed for the 3 CV risk factors known to be important in women: hyperlipidemia (low-fat, low-cholesterol diets), hypertension (low-sodium diets), and metabolic syndrome (low-carbohydrate diets). Thus, it is difficult for the average consumer to know what diet is best. Healthcare providers must counsel women to consume a diet that includes an abundance of fiber-rich foods, fish, and other sources of omega-3 fatty acids, fruits and vegetables, and whole grains to prevent CVD and provide the best chance for CV risk reduction. In addition, healthcare providers must continue to conduct research that focuses on CV diets, so that there may be a more unified approach in the future.

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Keywords:

cardiovascular diet; low-carbohydrate diet; low-fat diet; Mediterranean diet; omega-3 fatty acids

© 2005 Lippincott Williams & Wilkins, Inc.