Positive Health Online

Abstract

SHARMA and COLLEAGUES, Department of Nutrition, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4970, USA compared the effects of several diets upon clinical cardiac parameters.

Background

Chronic hypertension leads to cardiac hypertrophy, heart failure, and premature death. Little is known about the impact of dietary macronutrient composition on hypertension-induced cardiac hypertrophy and mortality. We investigated the effects of consuming either a high complex carbohydrate diet, a high simple sugar diet, or a high fat diet on cardiac hypertrophy and mortality in hypertensive Dahl salt-sensitive (DSS) rats.

Methodology

Rats were assigned to four diets: complex carbohydrate (CC; 70% starch, 10% fat, 20% protein by energy), high fat (FAT; 20% carbohydrates, 60% fat, 20% protein), high fructose (FRU; 70% fructose, 10% fat, 20% protein), and "western" (WES; 35% fructose, 45% fat, 20% protein). Hypertension was initiated by adding 6% NaCl (+S) to the chow of half the animals within each diet (n = 10 to 13/group). Tail cuff blood pressure measurements were assessed after 5 and 11 weeks of treatment, and echocardiography were assessed after 12 weeks of treatment.

Results

All rats fed a high salt diet had similar levels of hypertension (CC+S 220 +/-2 mm Hg, FAT+S 221 +/- 3 mm Hg, FRU+S 221 +/- 1 mm Hg, WES+S 226 +/- 3 mm Hg). Echocardiography results show that the addition of salt to FRU resulted in increased regional wall thickness that was not observed in other dietary groups. All rats fed a low salt diet (CC, FAT, FRU, WES) and the FAT+S group survived 90 days. On the other hand, there was 90-day mortality in the WES+S group (18% mortality) and the CC+S group (30% mortality). In addition, FRU+S rats started dying after 45 days of salt feeding, and only 15% survived the full 90 days.

Conclusion

These results demonstrate that a high fructose diet consumed during hypertension increases mortality and left ventricular (LV) wall thickness compared to either a high fat, high starch, or a "western" diet.

References

Sharma N, Okere IC, Duda MK, Johnson J, Yuan CL, Chandler MP, Ernsberger P, Hoit BD,  Stanley WC. High fructose diet increases mortality in hypertensive rats compared to a complex carbohydrate or high fat diet. American Journal of Hypertension. 20(4):403-9. April 2007.

Comment

Results continue to demonstrate that it is sugar rather than fat that is the major culprit regarding heart disease.