Evidence shows that adhering to a DASH diet leads to a reduction in cholesterol. The DASH diet promotes fruit, vegetable, and low-fat dairy food consumption while reducing saturated fat and cholesterol intake. It is recommended for the management of hypertension based on the extensive evidence of its blood pressure lowering effects, but its benefits are not limited to blood pressure.1 Multiple studies have shown that the DASH diet reduces total cholesterol and low-density lipoprotein (LDL) cholesterol levels, but has an unclear effect on high-density lipoprotein (HDL) cholesterol.1-8
A 2014 meta-analysis by Siervo et al. analyzed randomized controlled trials of adult participants adhering to a DASH diet.1 In thirteen trials (n=1844), total cholesterol and LDL cholesterol levels of participants following a DASH diet were compared to those of participants following a standard diet, which was the typical American diet in the majority of the studies. Participants following the DASH diet had a significant average decline in total cholesterol concentration of 7.7 mg/dL (95% confidence interval [CI] [-12 – -3.9], p<0.001) and in LDL cholesterol concentration of 3.9 mg/dL (95% CI [-7.7 − -0.39], p=0.03). However, there was no significant change in HDL cholesterol concentration.
Obarzanek et al. conducted a randomized controlled outpatient feeding trial of 436 participants, including 60% African American participants.2 After a three-week run-in period following the control diet (typical American diet), the participants were randomly assigned to one of the following dietary patterns for an eight-week intervention period: 1) DASH diet, 2) fruit and vegetable diet, and 3) control diet (typical American diet). Lipid levels were taken at the end of the run-in period and the end of the intervention period. Adherence to diet was measured by daily food diaries. At the end of the eight-week intervention, the authors found that in comparison to the control group, the DASH diet group had a significant average decline in total cholesterol concentration of 13.7 mg/dL (95% CI [-18.8 − -8.6], p<0.0001) and in LDL cholesterol concentration of 10.7 mg/dL (95% CI [-15.4 − -6.0], p<0.0001). Furthermore, the net reductions in total and LDL cholesterol were greater in men than women, but they did not differ significantly by race. The results also suggest a potential reduction of HDL cholesterol with the DASH diet.
To test the effects of increasing the fat content of the DASH diet, Chiu et al. conducted a randomized crossover trial of 36 healthy participants that included three periods.3 After a one-week run-in diet, participants were randomly assigned an order to consume each of the following diets for three weeks: 1) standard DASH diet; 2) higher fat, lower-carbohydrate modified DASH diet (HF-DASH diet); and 3) control diet (typical American diet). Intervention periods were separated by two-week washout periods. The participants’ weight measurements were taken weekly, and their blood samples were taken at the end of each experimental and washout period. The clinic provided standardized food representing about 50% of the total energy intake. The participants were required to submit receipts for the food they individually bought. During the periods that participants followed a DASH diet, the authors found a significant reduction in total cholesterol of 9.7 mg/dL (95% CI [-13 − -6.6], p<0.004) and in LDL cholesterol of 8.1 mg/dL (95% CI [-11 − -5.0], p<0.007). They also found a significant reduction in HDL cholesterol of 3.1 mg/dL (95% CI [-4.3 − -1.9], p=0.006). The HF-DASH diet lowered plasma triglyceride and very-low-density lipoprotein levels without significant changes in LDL cholesterol.
In a prospective study of 1409 participants, Maddock et al. assessed the long-term associations between the DASH diet and cardiovascular risk factors over a span of 24 to 28 years.9 The Medical Research Council National Survey of Health and Development followed a sample of babies born in one week in March 1946. This cohort has been followed 24 times over the course of their lives. Interval follow-ups were made for these participants at age 36, 43, 53, and 60 – 64 years, during which they completed diet diaries covering 3 or more days. Maddock et al. used t these diaries to measure adherence to the DASH diet through calculation of DASH scores. The participants were separated into quintiles based on adherence to the diet. At the 60 – 64-year follow-up, fasting blood samples were taken. The authors found no significant trend between adherence to the DASH diet and total cholesterol (p=0.19) or LDL cholesterol (p=0.83). However, participants with the highest adherence to the DASH-type diet had significantly higher HDL cholesterol (p<0.001) and lower triglycerides (p<0.001).
Zade et al. conducted a two-arm parallel randomized clinical trial to determine the effects of the DASH diet on 60 overweight and obese patients diagnosed with non-alcoholic fatty liver disease.10 Participants were randomly assigned to follow the DASH diet or control diet for an 8-week period. The control diet had the same macronutrient content as the DASH diet, but was higher in refined grains and sweets and lower in fruits and vegetables. Dietary adherence was monitored through weekly phone interviews and three-day dietary records throughout the study. Participants who followed the DASH diet had a significant reduction in total cholesterol concentration of 14.0 mg/dL (95% CI [-51.3 – 23.3], p=0.04) compared to those on the control diet. However, their LDL cholesterol concentration was not significantly reduced.
Overall, while a few studies show non-significant differences, many studies demonstrate that the DASH diet is effective in reducing total cholesterol and LDL cholesterol. However, the results for HDL cholesterol are varied.
References
- Siervo M, Lara J, Chowdhury S, et al. Effects of the Dietary Approach to Stop Hypertension (DASH) diet on cardiovascular risk factors: a systematic review and meta-analysis. Br J Nutr 2015; 113 (1): 1-15.
- Obarzanek E, Sacks FM, Vollmer WM, et al. Effects on blood lipids of a blood pressure-lowering diet: the Dietary Approaches to Stop Hypertension (DASH) Trial. Am J Clin Nutr 2001; 74 (1): 80-89.
- Chiu S, Bergeron N, Williams PT, et al. Comparison of the DASH (Dietary Approaches to Stop Hypertension) diet and a higher-fat DASH diet on blood pressure and lipids and lipoproteins: a randomized controlled trial. Am J Clin Nutr 2016; 103 (2): 341-347.
- Martin CL, Siega-Riz AM, Sotres-Alvarez D, et al. Maternal dietary patterns are associated with lower levels of cardiometabolic markers during pregnancy. Paediatr Perinat Epidemiol 2016; 30 (3): 246-255.
- Asemi Z, Tabassi Z, Samimi M, et al. Favourable effects of the Dietary Approaches to Stop Hypertension diet on glucose tolerance and lipid profiles in gestational diabetes: a randomised clinical trial. Br J Nutr 2013; 109 (11): 2024-2030.
- Harsha DW, Sacks FM, Obarzanek E, et al. Effect of dietary sodium intake on blood lipids: results from the DASH-sodium trial. Hypertension 2004; 43 (2): 393-398.
- Azadbakht L, Fard NR, Karimi M, et al. Effects of the Dietary Approaches to Stop Hypertension (DASH) eating plan on cardiovascular risks among type 2 diabetic patients: a randomized crossover clinical trial. Diabetes Care 2011; 34 (1): 55-57.
- Erlinger TP, Miller ER, 3rd, Charleston J, et al. Inflammation modifies the effects of a reduced-fat low-cholesterol diet on lipids: results from the DASH-sodium trial. Circulation 2003; 108 (2): 150-154.
- Maddock J, Ziauddeen N, Ambrosini GL, et al. Adherence to a Dietary Approaches to Stop Hypertension (DASH)-type diet over the life course and associated vascular function: a study based on the MRC 1946 British birth cohort. Br J Nutr 2018; 119 (5): 581-589.
- Razavi Zade M, Telkabadi MH, Bahmani F, et al. The effects of DASH diet on weight loss and metabolic status in adults with non-alcoholic fatty liver disease: a randomized clinical trial. Liver Int 2016; 36 (4): 563-571.
