在生命早期識別進展為高血壓的危險因素對預防心血管疾病至關重要。美國學者對飲食中攝入鈉鉀鹽和二者的比值對青少年血壓的影響進行了一項前瞻性研究，結果表明，青春期少女攝鈉≥3500 mg/d對血壓水平無不良影響，飲食中攝入鉀鹽也可對收縮壓和舒張壓產生有益影響，這提示，在兒童期攝入較多含鉀豐富的食物可能有助於抑製青少年期的血壓升高。相關論文4月28日在線發表於《美國醫學會雜誌·兒科學》(JAMA Pediatr)。

該美國心肺血液研究所的成長與健康研究是一項前瞻性隊列研究，納入了2185例初始年齡為9至10歲的黑人和白人女孩，有完整的青春期早期至中期的飲食和血壓數據，對其隨訪10年。校正種族、身高、活動量、電視/視頻觀看時間、能量攝入和其他飲食因素後，利用縱向混合模型和協方差分析模型評估青春期和隨訪10年後的飲食中鈉、鉀和二者的比值對收縮壓和舒張壓的影響。主要轉歸指標為青春期和隨訪結束時(17至21歲)的平均收縮壓和舒張壓水平。

結果研究者將鈉攝入分為4類：<2500 mg/d(19.4%的受試者)、2500 mg/d-3000 mg/d(29.5%)、 3000 mg/d-4000 mg/d (41.4%)和≥4000 mg/d(9.7%)。鉀攝入也分為4類：<1800 mg/d (36.0%)、1800 mg/d-2100 mg/d (26.2%)、2100 mg/d-2400 mg/d (18.8%)和≥2400 mg/d(19.0%)。

無證據顯示較多攝入鈉(3000-4000 mg/d和≥4000 mg/d vs <2500 mg/d)對青少年血壓有不良影響。縱向混合模型顯示，與鈉攝入2500 mg/d的個體相比，那些鈉攝入≥3500 mg/d的受試者舒張壓水平普遍較低(P = 0.18)。然而，在整個青春期和隨訪結束時，鉀攝入較多與血壓變化呈反相關關係(舒張壓和舒張壓的P值均<0 .001)(收縮壓和舒張壓的P值分別為 0.02和0 .05)。同時，鉀/鈉比值也與收縮壓呈反相關關係( P=0.04))，與單獨鉀攝入的影響相比，這些影響通常較弱。

參考文獻：Justin R. Buendia, et al. JAMA Pediatr. Published online April 27, 2015. doi:10.1001/jamapediatrics.2015.0411

Longitudinal Effects of Dietary Sodium and Potassium on Blood Pressure in Adolescent GirlsONLINE FIRST
Justin R. Buendia, BS1; M. Loring Bradlee, MS1; Stephen R. Daniels, MD, PhD2,3; Martha R. Singer, MPH, RD1; Lynn L. Moore, DSc, MPH1
[+] Author Affiliations
1Department of Medicine, Boston University School of Medicine, Boston, Massachusetts
2Department of Pediatrics, University of Colorado School of Medicine, Aurora
3The Children’s Hospital, Aurora, Colorado
JAMA Pediatr. Published online April 27, 2015. doi:10.1001/jamapediatrics.2015.0411
ABSTRACT
ABSTRACT | INTRODUCTION | METHODS | RESULTS | DISCUSSION | CONCLUSIONS |ARTICLE INFORMATION | REFERENCES
Importance Identification of risk factors early in life for the development of high blood pressure is critical to the prevention of cardiovascular disease.
Objective To study prospectively the effect of dietary sodium, potassium, and the potassium to sodium ratio on adolescent blood pressure.
Design, Setting, and Participants The National Heart, Lung, and Blood Institute’s Growth and Health Study is a prospective cohort study with sites in Richmond, California; Cincinnati, Ohio; and Washington, DC. Participants included 2185 black and white girls initially aged 9 to 10 years with complete data for early-adolescent to midadolescent diet and blood pressure who were followed up for 10 years. The first examination visits were from March 1987 through February 1988 and follow-up continued until February 1999. Longitudinal mixed models and analysis of covariance models were used to assess the effect of dietary sodium, potassium, and the potassium to sodium ratio on systolic and diastolic blood pressures throughout adolescence and after 10 years of follow-up, adjusting for race, height, activity, television/video time, energy intake, and other dietary factors.
Exposures Mean dietary sodium and potassium intakes and the mean potassium to sodium ratio in individuals aged 9 to 17 years. To eliminate potential confounding by energy intake, energy-adjusted sodium and potassium residuals were estimated.
Main Outcomes and Measures Mean systolic and diastolic blood pressures throughout adolescence and at the end of follow-up (individuals aged 17-21 years).
Results Sodium intakes were classified as less than 2500 mg/d (19.4% of participants), 2500 mg/d to less than 3000 mg/d (29.5%), 3000 mg/d to less than 4000 mg/d (41.4%), and 4000 mg/d or more (9.7%). Potassium intakes ranged from less than 1800 mg/d (36.0% of participants) to 1800 mg/d to less than 2100 mg/d (26.2%), 2100 mg/d to less than 2400 mg/d (18.8%), and 2400 mg/d or more (19.0%). There was no evidence that higher sodium intakes (3000 to <4000 mg/d and ≥4000 mg/d vs <2500 mg/d) had an adverse effect on adolescent blood pressure and longitudinal mixed models showed that those consuming 3500 mg/d or more had generally lower diastolic blood pressures compared with individuals consuming less than 2500 mg/d (P = .18). However, higher potassium intakes were inversely associated with blood pressure change throughout adolescence (P < .001 for systolic and diastolic) and at the end of follow-up (P = .02 and P = .05 for systolic and diastolic, respectively). While the potassium to sodium ratio was also inversely associated with systolic blood pressure (P = .04), these effects were generally weaker compared with effects for potassium alone.
Conclusions and Relevance In this study of adolescent girls, consumption of 3500 mg/d of sodium or more had no adverse effect on blood pressure. The beneficial effects of dietary potassium on both systolic and diastolic blood pressures suggest that consuming more potassium-rich foods during childhood may help suppress the adolescent increase in blood pressure.