NUTRITIONAL INFLUENCES ON NET ACID EXCRETION
| dc.contributor.advisor | Whiting, Susan | |
| dc.contributor.committeeMember | Zello, Gordon | |
| dc.contributor.committeeMember | Patience, John | |
| dc.creator | Bell, Janet Amy | |
| dc.date.accessioned | 2023-11-02T22:18:22Z | |
| dc.date.available | 2023-11-02T22:18:22Z | |
| dc.date.issued | 2003-08 | |
| dc.date.submitted | August 2003 | en_US |
| dc.description.abstract | Net acid excretion (NAE) is implicated in bone loss, as increased calcium loss is seen with high NAE. Protein is the main source of dietary acid load and fruit and vegetables provide potassium salts which counteract this effect. Two studies investigated how dietary factors affect NAE and markers of bone loss. The purpose of Study 1 was to determine if pH paper strip measurement of first morning urine reflected NAE and to investigate dietary effects on NAE and markers of bone loss in free-living individuals. Twenty-three subjects recorded 24-hour food records and collected 24-hour urine, as day (-7 a.m. to 11 p.m.) and overnight (-11 p.m. to 7 a.m.), and fasting second morning urine collections. NAE was measured as titratable acidity minus HCO3 (TA) plus NH4±. pH paper strip measurement of first morning urine was significantly correlated with 24-hour TA (r = -0.466, p < 0.025), but not with 24-hour NAE. The expected relationship between NAE and dietary protein or potassium intake was not evident, instead there was an association between protein and potassium intake (r = 0.679, p < 0.005). Nor was the ratio of protein to potassium associated with NAE. A positive association was found between urinary sodium (reflecting dietary sodium) and fasting urinary calcium excretion (indirect measure of bone loss). A surprising significant negative correlation was found between NAE and urinary cross-linked N-telopeptides (NTx), suggesting that NAE may not be a significant factor in bone turnover. The log transformation of urinary sodium versus NTx indicates a possible effect of sodium on bone turnover (r = 0.407, p = 0.084). Although pH paper strips are a good estimate of NAE, they measure a factor that appears less important than sodium intake. The purpose of Study 2 was to determine if fruit intake (a source of alkalinity) would lower NAE and thereby urinary calcium loss. A crossover, acute load study was designed to investigate if processed fruit was as effective as fresh fruit in reducing NAE and protein induced hypercalciuria. Fifteen volunteers completed 3 dietary treatments on 3 different days. A fasting urine sample was collected before consuming one of the following 3 isocaloric high protein treatments: control (C), sugar and protein; fresh (F), apples, sugar and protein; and processed (P), applesauce and protein. Fruit treatments were designed to each provide 9 mmol of potassium, according to published food labels. Urine was collected at 1.5 hour, 3 hour, and 4.5 hour. The mean NAE at 3 hour was (mmol/mmol Cr): C, 366 ± 2.18; F, 2.05 ± 2.05; and P, 1.63 ± 2.56, (p = 0.082), indicating a trend for lower NAE with fruit. The change in calcium excretion at 3 hour was (mmol): C, 0.239 ± 0.20; F, 0.126 ± 0.11; and P, 0.079 ± 0.21, (p = 0.048). Post hoc LSD test did not show a significant difference between treatments. Therefore, fruit intake is able to reduce protein induced hypercalciuria, and processed fruit appears to be as effective as fresh fruit, although a larger serving had to be consumed. While protein has received much attention for its role in increasing NAE and urinary calcium, these studies support other current literature which indicate that protein may not be harmful to bone when the diet is adequate in fruits and vegetables. Therefore, a diet generous in fruits and vegetables, adequate in protein, and low in sodium appears to be a dietary pattern which would promote bone health. | en_US |
| dc.identifier.uri | https://hdl.handle.net/10388/15207 | |
| dc.subject | Net acid excretion | en_US |
| dc.subject | bone loss | en_US |
| dc.subject | dietary factors | en_US |
| dc.title | NUTRITIONAL INFLUENCES ON NET ACID EXCRETION | en_US |
| dc.type.genre | Thesis | en_US |
| thesis.degree.department | Pharmacy and Nutrition | en_US |
| thesis.degree.grantor | University of Saskatchewan | en_US |
| thesis.degree.level | Masters | en_US |
| thesis.degree.name | Master of Science (M.Sc.) | en_US |