The Feasibility of Achieving Low-Sodium Intake in Diets That Are Also Nutritious, Low-Cost, and Have Familiar Meal Components
and Have Familiar
Meal Components. PLoS ONE 8(3): e58539. doi:10.1371/journal.pone.0058539
The Feasibility of Achieving Low-Sodium Intake in Diets That Are Also Nutritious, Low-Cost, and Have Familiar Meal Components
Nick Wilson 0
Nhung Nghiem 0
Rachel H. Foster 0
Nick Ashton, The University of Manchester, United Kingdom
0 Department of Public Health, University of Otago , Wellington , New Zealand
Objective: Given the importance of high sodium diets as a risk factor for disease burden (ranked 11th in importance in the Global Burden of Disease Study 2010), we aimed to determine the feasibility of low-sodium diets that were also low-cost, nutritious and (for some scenarios) included familiar meals. Methods: The mathematical technique of ''linear programming'' was used to model eight optimized daily diets (some with uncertainty), including some diets that contained ''familiar meals'' for New Zealanders or were Mediterranean-, Asian- and Pacific-style diets. Data inputs included nutrients in foods, food prices and food wastage. Findings: Using nutrient recommendations for men and a cost constraint of ,NZ$9/d (US$6.84), the sodium intake levels in the eight optimized daily diets were all well below the 2300 mg/d (5.8 g salt/d) recommended maximum. The only diet to not consistently fall below the recommended ''target'' upper limit of 1600 mg/d included an evening meal with sausages (median = 1640 mg/d, 95% simulation interval: 1551-1735 mg/d). Many additional nutritional aspects of these optimized low-sodium diets suggest that they would reduce cardiovascular disease risk in other ways (e.g., improved polyunsaturated to saturated fat ratio) and also reduce risk of cancer and other chronic diseases (e.g., via higher intakes of vegetables, fruits and dietary fiber). Even healthier diets (e.g., with higher intakes of fruit) occurred when the cost constraint was relaxed to $NZ15/d (US$11.40). Similar results were obtained when the modeling considered diets for women. Conclusions: These results provide some reassurance for the feasibility of substantially reducing population sodium intake given currently available low-cost foods and while maintaining some level of familiar meals. Policy makers could consider ways to promote such optimized diets and foods, including regulations on maximum salt levels in processed foods, and taxes on alternative foods that are high in salt, sugar and saturated fat.
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Introduction
A high intake of salt in the diet is associated with a significantly
increased risk of stroke and total cardiovascular disease according
to a meta-analysis of 13 observational studies [1]. There is also
evidence from a Cochrane systematic review that reductions in
sodium intake reduce systolic blood pressure (BP) in people defined
as normotensive by about 1.3 to 4 mm Hg and even more so in
people with hypertension (6 to 10 mm Hg reduction) [2]. In turn,
there is a direct relationship between BP and heart disease, stroke
and end-stage renal disease according to a meta-analysis of 61
studies [3].
Yet the direct evidence for dietary salt reduction leading to a
reduction in disease outcomes is less conclusive. A recent
Cochrane systematic review reported that salt reduction had
relatively small benefits on cardiovascular events or mortality, and
that uncertainty remained [4]. However, this review has been
criticized for its approach to study inclusion and other
methodological issues [5], [6], [7]. Its low power has also been noted; the
analysis only had 10% power to detect a 10% reduction in relative
risk [6].
When looking at the totality of the evidence for the potential
benefits to health from the reduction of dietary salt intake, there is
also evidence from many animal studies, ecological studies and
observational studies [8], [7]. Particularly notable improvements
in cardiovascular health associated with dietary salt reduction were
achieved in Finland after institution of systematic approaches to
reduce salt intake across the population, such as mass
mediacampaigns, co-operation with the food industry, and implementing
salt labeling legislation. Nevertheless, other cardio-protective
changes may also have played important roles in these trends
e.g., increased potassium intake, increased fruit and vegetable
intake, and reduced smoking [7].
In the most recent review we identified was by the World
Health Organization (WHO), and the findings were that:
Higher sodium intake was associated with higher risk of
incident stroke, fatal stroke and fatal coronary heart disease.
There was no association between sodium intake and
allcause mortality, incident cardiovascular disease and
nonfatal coronary heart disease. However, the strong positive
relationship between blood pressure and these outcomes
provides indirect evidence that reducing sodium intake can
improve these outcomes through a beneficial effect on blood
pressure. [9]
As others have commented on, it is clear that there are
considerable complexities in co (...truncated)