What is the dietary treatment for low HDL cholesterol?

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Clinical Inquiries

What is the dietary treatment for low HDL cholesterol?

J Fam Pract. 2006 December;55(12):1076-1078

By

Paul Crawford, MD

Shelley L. Paden, MLS, AHIP

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References

1. Gordon DJ, Knoke J, Probstfield JL, Superko R, Tyroler HA. High-density lipoprotein cholesterol and coronary heart disease in hypercholesterolemic men: the Lipid Research Clinics Coronary Primary Prevention Trial. Circulation 1986;74:1217-1225.

2. Williams PT. The relationships of vigorous exercise, alcohol, and adiposity to low and high high-density lipoproteincholesterol levels. Metabolism 2004;53:700-709.

3. Nordmann AJ, Nordmann A, Briel M, et al. Effects of low-carbohydrate vs low-fat diets on weight loss and cardiovascular risk factors: a meta-analysis of randomized controlled trials. Arch Intern Med 2006;166:285-293.

4. Wood RJ, Volek JS, Y Liu, NS Schacter, JH Contois, ML Fernandez. Carbohydrate restriction alters lipoprotein metabolism by modifying VLDL, LDL, and HDL subfraction distribution and size in overweight men. J Nutr 2006;136:384-389.

5. Azadbakht L, Mirmiran P, Esmaillzadeh A, Azizi T, Azizi F. Beneficial effects of a Dietary Approaches to Stop Hypertension eating plan on features of the metabolic syndrome. Diabetes Care 2005;28:2823-2831.

6. Zhan S, Ho SC. Meta-analysis of the effects of soy protein containing isoflavones on the lipid profile. Am J Clin Nutr 2005;81:397-408.

7. Morcos N. Increase in serum high-density lipoprotein following multivitamin and multimineral supplementation in adults with cardiovascular risk factors. Med Sci Res 1999;27:121-125.

8. Kelly S, Frost G, Whittaker V, Summerbell C. Low glycaemic index diets for coronary heart disease. Cochrane Database Syst Rev 2004;(4):CD004467.-

9. Brunner EJ, Thorogood M, Rees K, Hewitt G. Dietary advice for reducing cardiovascular risk. Cochrane Database Syst Rev 2005;(4):CD002128.-

10. Chen J, He J, Wildman RP, Reynolds K, Streiffer RH, Whelton PK. A randomized controlled trial of dietary fiber intake on serum lipids. Eur J Clin Nutr 2006;60:62-68.

11. Lewis A, Lookinland S, Beckstrand RL, Tiedeman ME. Treatment of hypertriglyceridemia with omega-3 fatty acids: A systematic review. J Am Acad Nurse Pract 2004;16:384-395.

12. Farmer A, Montori V, Dinneen S, Clar C. Fish oil in people with type 2 diabetes mellitus. Cochrane Database Syst Rev 2001;(3):CD003205.-

13. Hooper L, Thompson RL, Harrison RA, et al. Omega 3 fatty acids for prevention and treatment of cardiovascular disease. Cochrane Database Syst Rev 2004;(4):CD003177.-

14. Tapsell LC, Gillen LJ, Patch CS, et al. Including walnuts in a low-fat/modified-fat diet improves HDL cholesterol-to-total cholesterol ratios in patients with type 2 diabetes. Diabetes Care 2004;27:2777-2783.

15. Spiller GA, Jenkins DA, Bosello O, Gates JE, Cragen LN, Bruce B. Nuts and plasma lipids: an almond-based diet lowers LDL-C while preserving HDL-C. J Am Coll Nutr 1998;17:285-290.

16. Lichtenstein AH, Appel LJ, Brands M, et al. Diet and lifestyle recommendations revision 2006: A scientific statement from the American Heart Association Nutrition Committee. Circulation 2006;114:82-96.

EVIDENCE-BASED ANSWER

Low-carbohydrate diets raise high-density lipoprotein (HDL) cholesterol levels by approximately 10%; soy protein with isoflavones raises HDL by 3% (strength of recommendation [SOR]: C, based on meta-analysis of physiologic parameters). The Dietary Approaches to Stop Hypertension (DASH) diet and multivitamin supplementation raise HDL 21% to 33% (SOR: C, based on single randomized trial each measuring physiologic parameters). No other dietary interventions studied raise HDL (SOR: C, based on meta-analysis of physiologic parameters).

CLINICAL COMMENTARY

Michael K. Park, MD
University of Colorado Health Sciences Center, Rose Family Medicine Residency, Denver

Even modest increases in HDL can be clinically important; exercise, weight loss, and tobacco cessation can help When it comes to HDL, most of our patients are not as fortunate as natives of Limone sul Garda, Italy (famously low but efficient HDL) or Honshu, Japan (high HDL). Medications based on these protective genetic anomalies are being developed. Also, the flushing resulting from niacin may soon be more effectively mitigated than with aspirin. Until these new therapies are available, urge multifaceted lifestyle modification—if only for its more robust cardiovascular benefits.

A low HDL can elicit a clinical fatalism from even the best of us. But each increase in baseline HDL of 1 mg/dL is associated with a 5% decrease in the risk of death from coronary disease,¹ so even modest increases in HDL can be clinically important. In addition to the dietary measures described above, evidence exists that exercise, alcohol in moderation, weight loss, and tobacco cessation also increase HDL. Unfortunately, the magnitude of even these small improvements appear to be directly proportional to baseline HDL levels.²

So … when are those new medications coming?

Evidence summary

Low HDL is recognized as a risk factor for atherosclerosis. Clinicians find raising HDL a challenge, and patients often inquire about dietary advice that may help raise HDL.

No quality evidence exists that specifically looks at the effect of a dietary intervention on HDL or whether it affects survival. However, several dietary intervention studies in specific populations include HDL as a secondary endpoint in the study. This leaves clinicians to act on physiologic data that may or may not increase the overall health and survival of patients. Dietary interventions that raised HDL include low-carbohydrate diets, the DASH diet, supplementation with soy protein including isoflavones, and multivitamin supplementation.

TABLE
Summary of studies evaluating the effect of various diets on HDL cholesterol

STUDY	INTERVENTION	METHODS	HDL EFFECT
Nordmann, et al 2006³; Wood et al 2006⁴	Low-carbohydrate diets	Systematic review with meta-analysis of 5 RCTs of low-carbohydrate vs low-fat diets. 10% increase in HDL. Absolute increase 4.6 mg/dL (95% CI, 1.5–8.1). Subsequent uncontrolled prospective trial consistent with systematic review (12% increase in HDL)	++
Zhan and Ho 2005⁷	Soy protein with isoflavones	Systematic review with meta-analysis of 23 RCTs evaluating effect of various amounts of soy protein with isoflavones on lipid profile. 3% increase in HDL. Absolute difference 1.5 mg/dL (95% CI, 0.0–2.8)	+
Morcos 1999⁶	Multivitamin	RCT of 46 subjects in placebo controlled crossover study. 31% increase in HDL	++++
Azadbacht et al 2005⁵	DASH diet in metabolic syndrome	RCT of 116 patients randomized to control diet, weight control or DASH diet. Absolute increase of 7 mg/dL for men (21%). Absolute increase of 10 mg/dL for women (33%). No confidence intervals given	+++
Kelly et al 2004⁸	Low glycemic diet	Systematic review of 15 RCTs with low glycemic diets for patients with coronary heart disease. Heterogeneity prevented meta-analysis. No effect on HDL.	0
Brunner et al 2005⁹	Dietary advice	Systematic review of 23 RCTs comparing dietary advice and no advice to reduce cardiovascular risk. 956 participants. No effect on HDL.	0
Chen et al 2006¹⁰	Soluble fiber	RCT of 110 adults randomized to 8 g of soluble fiber vs control. No effect on HDL.	0
Lewis et al 2004¹¹	Omega-3 fatty acids in hyper-triglyceridemia	Systematic review of 10 RCTs comparing omega-3 fatty acids. Considered poor to moderate quality. Variable results from RCTs	???
Farmer et al 2001¹²	Omega-3 fatty acids in type 2 diabetes	Systematic review with meta-analysis of 18 trials with 823 patients. No effect on HDL	0
Hooper et al 2004¹³	Omega-3 fatty acids for prevention of CVD	Systematic review with meta-analysis of 48 trials of 36,913 participants taking omega-3 fatty acids for prevention of cardiovascular disease. No effect on HDL	0
Tapsell et al 2004;¹⁴ Spiller et al 1998¹⁵	Walnuts and almonds	One RCT and one prospective cohort trial of nuts added to the diet. No significant effect	0

Several overall diet interventions appear to raise HDL, but whether this affects cardiovascular events or mortality is unknown. A systematic review with meta-analysis of 5 randomized controlled trials (RCTs) of low-carbohydrate versus low-fat diets showed a 10% increase in HDL attributed to the low-carbohydrate diet, which translated to an absolute increase of 4.6 mg/dL (95% confidence interval [CI], 1.5–8.1).¹ A subsequent uncontrolled prospective trial was consistent with consistent with this systematic review and showed a 12% increase in HDL.² The DASH diet was studied as an intervention in a RCT of 116 patients with the metabolic syndrome. Men responded with an in crease of 21% and women with an increase of 33%.³

Evidence-based answers from the Family Physicians Inquiries Network