Retention of Potassium From Potatoes and Potassium Gluconate, and the Effect on Blood Pressure.

Potassium is a shortfall nutrient according to the 2010 Dietary Guidelines for Americans.
Only 3% of Americans meet the recommended Adequate Intake of 4700 mg/d for potassium. Average
potassium intake is approximately half of the Recommended Dietary Allowance (RDA), with
potatoes providing the highest percentage (19-20% of potassium) in the American diet.
Recommended dietary potassium intakes were determined primarily to optimize protection
against hypertension and secondarily to protect against stroke and coronary heart disease. In
setting requirements for most minerals, bioavailability is usually considered. However,
little is known about bioavailability of potassium and what is known is from supplements
rather than food. Recently, we performed a potassium bioavailability study on white potatoes
looking at 35 healthy, normotensive men and women at 3 levels of potassium intake as potatoes
or potassium gluconate supplements. Bioavailability of potassium was determined from AUC of
serial blood draws and cumulative urinary excretion. Serum potassium Area Under the Curve
(AUC )increased with dose (P<0.0001) and did not differ due to source (p=0.52). Cumulative 24
h urinary potassium also increased with dose (p<0.0001) and was greater with potato than
supplement (p<0.0001), concluding that bioavailability of potassium is as high from potatoes
as from supplements. These data allow us to evaluate the quality of the food as a source of
potassium. However, a remaining question is whether retention of potassium from potatoes is
higher than from the salt, which requires a metabolic balance study to determine. The effects
of potassium rich foods on blood pressure have also been recently accessed. A controlled
feeding study would properly capture potassium retention and balance, as well as adequately
control for any positive benefit potassium may have on blood pressure and other vascular
outcomes.

Increasing potassium citrate decreased titratable acidity and improved calcium retention in a
dose response manner in postmenopausal women. There is one Randomized Controlled Trial (RCT)
of potassium on bone, in postmenopausal women, showing a benefit of a supplement of potassium
chloride on protecting against bone loss. Similar studies have not been performed with food
sources of potassium.

This study is designed to evaluate the effect of added potassium (K) from potatoes in the
diet on K retention , blood pressure, and parameters related to bone health including calcium
retention and acid base balance.

Inclusion Criteria:

- Age 21 and above

- Subjects able to adhere to the visit schedule and protocol requirements and be
available to complete the study.

- Pre-hypertensive, (SBP: 120-159mmHg).

Exclusion Criteria:

- Subjects taking more than one medication to treat hypertension

- Subject is taking medication to treat hypotension, or medication known to affect
electrolyte metabolism or contain high levels of potassium or sodium, smoke
cigarettes, use illegal drugs, or excessive alcohol intake.

- Current use systemic corticosteroids, androgens, phenytoin, erythromycin, thyroid
hormones, lipid-lowering medication.

- Subjects who have hypertension (SBP > 160 mmHg), hypotension (SBP < 120mmHg) or
diseases known to affect potassium metabolism (kidney disease or malabsorption
disorders). History of myocardial infarction, diabetes mellitus, renal disease,
gastrointestinal disease, pancreatitis, cholestatic liver disease, cancer.

- Subjects who are pregnant.

- Allergy or intolerance of intervention foods.

- Unwillingness to refrain from dietary supplements.

- Weight loss > 3kg in the past 2 months.

- Subjects with liver and/or lipid abnormalities (elevated alanine amino transferase
(ALT) and aspartate amino transferase (AST), dyslipidemia).