Despite a gradual decline in mortality from cardiovascular disease (CVD), it is still the leading cause of both morbidity and mortality in the United States . Approximately 864,000 Americans die each year from CVD and this figure makes up 35% of the total deaths in the United States . In recent years, there have been disturbing increases in the prevalence of CVD risk factors like diabetes, obesity, and the metabolic syndrome which collectively may negate the downward trends in CVD mortality [1, 3, 4].
Obesity elevates the risk of developing metabolic syndrome, diabetes, and CVD [5–7]. Obesity is thought to initiate a cascade of events leading to systemic inflammation and increases in circulating C-reactive protein, insulin resistance, and dyslipidemia . In 1998, the American Heart Association considered obesity to be one of the major risk factors for coronary heart disease . Other risk factors for CVD include a higher body mass index (BMI), the marker commonly used to establish obesity, which has been shown to be independently associated with hypertension, elevated total cholesterol and low-density lipoprotein (LDL) cholesterol levels, and lower high density lipoprotein (HDL) cholesterol [9–12]. The optimal BMI for adults 18 to 85 years of age is from 23 to 25 for most races . Evidence has demonstrated that people with elevated BMI are at higher risk of developing CVD compared with those of normal BMI [14, 15]. Additionally, the presence of metabolic syndrome is predicted to shorten life leading to death at younger ages .
Diets high in fat and cholesterol are the major factors contributing to CVD. Dietary modification and lifestyle changes are suggested to be effective strategies to prevent CVD . The National Heart, Lung, and Blood Institute (NHLBI) recommend the Therapeutic Lifestyle Change (TLC) diet to improve heart health in individuals at risk for CVD. The TLC diet consists of reducing intake of saturated and total fat from animal products and increasing the intake of fibrous vegetables, fruits, whole grains, and legumes . Increased fruit and vegetable consumption has been found to play a key role in preventing heart disease. In a follow up of the Nurse's Health Study, an additional serving per day of fruits and vegetables was associated with a 4% reduction in the risk of coronary heart disease . Fruits and vegetables contain many nutrients which may be associated with reduced risk for heart disease, including fiber, vitamins, minerals, and phytochemicals. Phytochemicals found in fruits and vegetables have been shown to reduce inflammation, oxidative stress, and other markers of CVD .
Among common fruits and vegetables, carrots are high in fibers, carotenoids, vitamins C and E, and phenolics such as p-coumaric, chlorogenic, and caffeic acids . Consuming foods containing phenolic compounds has decreased the risk of vascular diseases in previous studies [22, 23]. Phenolic compounds are dietary antioxidants found in plants that are shown to inhibit LDL oxidation, inhibit platelet aggregation and adhesion, decrease total and LDL cholesterol, and induce endothelium-dependent vaso-relaxation [24–26]. Oral intake of carrot juice also displays other beneficial physiological effects including reduced oxidative DNA damage , increased levels of plasma antioxidants , and reduced inflammation . In the Lipid Research Clinics Coronary Primary Prevention Trial (LRC-CPPT), men were tracked over 13 years and results revealed that those with the highest plasma carotenoid levels had lower risk of coronary heart disease . In a 12-year follow-up of the Prospective Basel Study, Eicholzer and colleagues found that the risk of ischemic heart disease is increased by 1.53 Relative Risk in those with the lowest plasma carotene concentrations . Inflammation has been shown to be a strong predictor of CVD and serum β-carotene inversely correlates with C-reactive protein and interleukin-6 [29, 32].
Previous studies have shown beneficial effects of eating high fiber diets on lowering cardiovascular risk factors [33–35]. One other study has shown potential benefit of fruit and vegetable juice concentrate on cardiovascular prevention . The goal of present study was to evaluate the potential role of drinking 16 ounces fresh squeezed carrot juice (equivalent to one pound of fresh carrot) daily on lowering cardiovascular risk markers in adults with elevated cholesterol and triglycerides.