Biomedical subjects

J T Judd

Publications and source records attributed to J T Judd.

At least 55 records · Page 3Linked to original sources

PubMed1989

Modulating influence of dietary lipid intake on the prostaglandin system in adult men.

We evaluated the effect of moderate dietary changes on the prostaglandin system by measuring the urinary excretion of 7 alpha-hydroxy-5,11-dioxo-tetranorprostane-1,16-dioic acid (PGE-M). In a crossover design, twenty-four free-living male subjects in good health (24 to 54 years of age) were fed two diets: (i) Regular (R) diet, 41% energy (en%) from fat, P/S 0.59, M/S 0.96; (ii) Experimental (E) diet, 19 en% from fat, P/S 1.31, M/S 1.48. Diet R contained 13.9 g/day of neutral detergent fiber (NDF) and about 600 mg/day of cholesterol per 3200 kcal; Diet E contained 35.5 g/day NDF and about 280 mg/day cholesterol. Each controlled-diet period lasted ten weeks. The menu cycle was 7 days, and all diets were calculated to provide adequate amounts of essential nutrients. The PGE-M excretion rates were determined in 24-hr urine by stable-isotope dilution gas chromatography-mass spectrometry in the selected ion-monitoring mode. Low-fat Diet E, with an intake of 6.6 en% from polyunsaturates, was associated with an average 14.2% reduction in PGE-M daily output, compared to high-fat Diet R with a 9.3 en% from polyunsaturates (P = 0.046). These results support the view that dietary lipid changes can significantly alter the in vivo production of E-series prostaglandins. We cannot conclude, however, if this apparent diet effect was brought about by the change in linoleate intake alone or was the result of complex biochemical interactions among individual fatty acids, both saturated and unsaturated.

Adult↗

PubMed1989

Dietary fat and hormonal effects on erythrocyte membrane fluidity and lipid composition in adult women.

Erythrocyte ghost membrane fluidity and phospholipid linoleate were significantly increased when higher levels of polyunsaturated fats were fed to healthy, free living, premenopausal women. Fluidity was assessed by diphenylhexatriene (DPH) fluorescence polarization measurements with hypotonically lysed red blood cells from 31 female subjects fed one of two sets of diets, which were formulated from typical US foods to contain polyunsaturate to saturate ratios (P/S) of 1.0 or 0.3. Both groups of women were fed diets with 40% of energy as fat for four menstrual cycles followed by low-fat diets having 20% of energy as fat for the next four menstrual cycles. Blood was sampled during the fourth cycle of each dietary period at times estimated to correspond to maximum secretions of estrogen and progesterone to assess interactive hormonal and dietary effects on membrane composition and fluidity. Red blood cell membranes were most fluid following higher levels of linoleate intake, either by higher (40%) total fat or higher P/S levels. Membrane fluidity was directly related to the phospholipid oleate and linoleate contents and inversely related to the molar cholesterol/phospholipid ratio. Hormonal status effects on the membranes were not extensive. Membrane fluidity in cells from women fed P/S = 0.3 diets was higher at 40% than at 20% fat during the luteal phase of the fourth cycle. In contrast, women fed the P/S = 1.0 diets had more fluid red cells at 40% fat during the follicular phase of the cycle. Regression analysis showed a direct linear correlation between membrane fluidity and red cell membrane insulin binding demonstrating a relation between receptor binding and cell membrane fluidity in the human female.

Adult↗

PubMed1989

Relationship of dietary fat to plasma fatty acids, blood pressure, and urinary eicosanoids in adult men.

This experiment was conducted to determine the relationships between modest changes in dietary linoleate, blood pressure (BP) response, and levels of eicosanoid synthesis in humans. Products of eicosanoids which appear in blood were measured in urine: PGI2, 6-keto-PGF1 alpha (KPGI2); TXA2, (TXB2); PGF2 alpha, 13,14-dihydro-15-keto-PGF2 alpha, (MPGF2 alpha). Twenty-three adult men were fed controlled diets having 25 energy percent fat, and having P/S ratios of either 0.3 (low-PUFA) or 1.0 (high-PUFA), for a total of 12 weeks, with a switchover between P/S ratios at 6 weeks. The results showed that, under the conditions of this study, BP was significantly reduced by reducing dietary fat intake from about 37 to 25 energy percent. However, no further effects on BP were produced by increasing the P/S ratio from 0.3 to 1.0. KPGI2 excretion was significantly lowered on both controlled diets as compared to the self-selected (SS) diet. However, MPGF2 alpha was lowered only on the low-PUFA diet as compared to the self-selected diet. No significant decrease in TXB2 excretion was observed. Both MPGF2 alpha and KPGI2 excretion were positively correlated with urine volume and sodium excretion. On the SS diet, but not on the controlled diets, MPGF2 alpha excretion was negatively correlated with plasma linoleate and positively correlated with stearate. On the low-PUFA diet, MPGF2 alpha excretion increased with the intake of linoleate, while, on the high-PUFA diet, it decreased. This may have been due to the limited amounts of linoleate available in the low-PUFA diet (3.2-3.4 energy percent) as compared to that in the high-PUFA diet. Both KPGI2 and MPGF2 alpha excretion were positively correlated with systolic and diastolic BP. These results suggest that the amount of dietary linoleate is an important factor in the regulation of prostaglandin synthesis in humans.

Adult↗

PubMed1989

Dietary fat and menstrual-cycle effects on the erythrocyte ghost insulin receptor in premenopausal women.

The effect of high- and low-fat diets with different levels of fatty acid unsaturation on insulin receptors of erythrocyte ghosts was studied during different phases of the menstrual cycle in 31 healthy premenopausal women. Subjects were divided into two groups and consumed controlled diets containing 39% fat with a ratio of polyunsaturated to saturated fatty acids (P:S) of either 0.30 or 1.00 for four menstrual cycles. They were switched to 19% fat at the same P:S for another four cycles. Fasting blood samples were collected during the follicular and luteal phases. Insulin receptors were measured from right-side-out ghosts. Insulin binding was significantly lower due to fewer receptors when subjects were fed the low-fat, high-carbohydrate diet compared with the high-fat, low-carbohydrate diet. There was no significant effect of level of unsaturation or time of menstrual cycle on insulin binding. Thus, insulin receptors on erythrocytes respond to dietary lipids.

Dietary Fats↗

PubMed1988

Cheek cell fatty acids as indicators of dietary lipids in humans.

Analysis of cheek cell lipids has been suggested as a noninvasive method for monitoring the fatty acid composition of diets in humans. In a pilot study conducted to determine the validity of the method, cheek cell samples were collected from subjects consuming a low fat (20% of calories) diet consisting of fatty acids with either a 1.0 or 0.3 P/S ratio. Neither total lipid nor polar lipid fatty acids in cheek cells consistently reflected the P/S ratio of the diets. However, there were trends, particularly in the nonpolar lipids, suggesting that cheek cell fatty acid ratios might be useful for monitoring the fatty acid composition of the diets. The diet with the higher P/S ratio (1.0 vs 0.3) consistently resulted in cheek cell lipids with lower ratios of 18:1/saturated fatty acids and greater 18:2/20:4, 18:2/18:1 and 18:2/18:0 fatty acid ratios.

Cheek↗

PubMed1988

Menstrual cycle effect on plasma lipids.

In a study of 31 healthy women in which dietary intake and body weight were controlled, a significantly higher mean plasma cholesterol was observed in the follicular phase of the menstrual cycle compared to the luteal phase (mean difference of 8.4% during controlled dietary periods). Higher mean plasma triglycerides (mean difference of 7.4%) and lower HDL-cholesterol (mean difference of 5.8%) were also observed in the follicular phase of the controlled dietary study, although these differences were not consistently significant.

Adult↗

PubMed1988

Effects of low fat diets differing in degree of fat unsaturation on plasma lipids, lipoproteins, and apolipoproteins in adult men.

The effects of two low fat diets with differing ratios of polyunsaturated to saturated fatty acids (P/S) on blood lipids, lipoproteins (LP), and apolipoproteins (Apo) were studied in 23 adult men, 30-60 years old, using a crossover design. Both test diets had 25% fat calories with either a P/S of 0.3 (Diet 1) or a P/S of 1.0 (Diet 2) and equivalent amounts of cholesterol. The study consisted of four periods: a 5-week prestudy on self-selected diet (SS), two 6-week test diet periods followed by a second 5-week post-study period on the SS diet. When compared with the SS diet, Diet 2 lowered the mean plasma total cholesterol (TC) by about 20% (P less than 0.01). Low density lipoprotein (LDL) cholesterol was also decreased by about 18% by Diet 2 (P less than 0.01). The high P/S diet did not cause a change in total cholesterol in the high density lipoprotein (HDL) subclass2 (HDL2) when compared to the SS diet. Levels of triglycerides (TG) were slightly reduced in HDL2 but showed a greater reduction in HDL3 in both diets. Phospholipids (PL) were significantly reduced in HDL2 and in HDL3, but the reduction in HDL3 PL was not statistically significant. Apo A-I levels were not changed by either diet when compared with the SS diet, but Apo A-II levels of HDL2 and HDL3 were significantly decreased by the low fat diets, and there was no P/S effect. No other consistent changes in apoprotein levels occurred. Our data suggest that, in men with normal lipid levels, practical dietary changes involving a moderate increase in P/S from 0.3 to 1.0 in a low fat, low cholesterol diet do influence lipoprotein composition and apoprotein distribution in a short time. The reduction in cholesterol in total lipid composition and in LDL lipids which accompanied the reduction of dietary fat and cholesterol are considered to be beneficial.

Adult↗

PubMed1988

Vitamin E and relationships among tocopherols in human plasma, platelets, lymphocytes, and red blood cells.

Plasma, RBC, platelets, and lymphocytes from human subjects on graded intakes of vitamin E were analyzed for tocopherols to determine which humoral compartment most closely followed changes in the dietary intake. Relative merits of the various blood elements to reflect changes in vitamin E intake were calculated by the sensitivity concept of Mandel and Stiehler (ie, rate of change of tocopherol levels with dose divided by the standard deviation). Sensitivities of alpha-tocopherol levels of the various blood components to vitamin E intake decreased in the order platelets greater than RBC greater than plasma lipids greater than plasma greater than lymphocytes. Changes in tocopherol levels in platelets most closely followed changing dietary intakes of vitamin E when compared with data from RBC, lymphocytes, and plasma. Furthermore, for studying the effects of diets on vitamin E status, tocopherol levels of platelets appear to be a better measure than tocopherol levels of either RBC, lymphocytes, or plasma lipids.

Blood Platelets↗

PubMed1988

Caloric and selected nutrient intakes and estimated energy expenditures for adult women: identification of non-sedentary women with lower energy intakes.

Dietary intakes and energy expenditures of healthy adult women were studied. Phase I (no. = 98): 37 women (38% of Phase one subjects) reported 3-day intakes of less than 1,600 kcal/day; low nutrient intakes were associated with less than 1,600 kcal/day for women who did not take supplements. Phase II (no. = 18): group mean energy expenditures assessed by activity diaries matched 7-day intake records for 8 women who had consumed greater than 1,800 kcal/day during Phase I but not for 10 women who had consumed less than 1,600 kcal/day during Phase I. Phase III: duplicate food composites and records supported previous intake records. The data from this study suggest that some non-sedentary women maintain consistently low energy/nutrient intakes and that calculation of energy expenditure from standard tables is not appropriate for those women.

Adult↗

PubMed1987

Dietary linoleate increases fluidity and influences chemical composition of plasma low density lipoprotein in adult men.

Dietary linoleate was effective to increase LDL fluidity in adult men but did not significantly influence VLDL or HDL fluidities. Lipoproteins were isolated ultracentrifugally from plasma of sixteen healthy, free living male volunteers consuming controlled diets formulated from typical U.S.A. foods to have 35 energy % fat with 10 g (diet L) or 30 g (diet H) linoleate per day, 30-50 g saturated fatty acids/day and the balance mainly monounsaturated fatty acids. Calculated cholesterol intakes were 500 mg/day at each calorie level. Changes in LDL fluidity were detected as differences in diphenylhexatriene (DPH) fluorescence polarization upon crossover between the two controlled diets. Thermotropic measurement of DPH fluorescence anisotropy and compositional analyses indicated that LDL and HDL fluidities were dependent upon phospholipid and triacylglycerol concentrations, respectively, and were modulated by the presence of cholesteryl esters. Fatty acid analyses of the major lipid classes of the isolated lipoproteins indicated that changes, upon diet crossover, in DPH fluorescence anisotropy, were a linear function of the incremental change in LDL phospholipid linoleate. The fluorescent probe described an environment corresponding to the fatty acyl moieties of the phospholipids on the LDL periphery, which composition is apparently under dietary control. It is suggested that the diet induced fluidity changes may affect the conformation of the apoprotein moiety on the LDL surface and thus the potential for LDL interaction with cellular LDL receptors.

Adult↗

PubMed1987

Influence of caloric contribution and saturation of dietary fat on plasma lipids in premenopausal women.

Total cholesterol, HDL cholesterol, and triglycerides were measured in 31 premenopausal women randomized into one of two diet groups: one diet with a P:S ratio of 1.0 and one diet with a P:S ratio of 0.3. Both groups were fed a high-fat diet (40% of energy from fat) for four menstrual cycles per subject followed by a similar interval on a low-fat diet (20% of energy from fat). Changing from the high-fat to the low-fat diet resulted in a nonsignificant mean decrease of 7% in total cholesterol. HDL-cholesterol response to the low-fat regimen was influenced by the P:S ratio. Women in the high P:S group showed no change; mean HDL cholesterol in women in the low P:S group decreased 12%. Plasma triglycerides increased in both groups on the low-fat diet although the increase was greatest in the low P:S group.

Adult↗

PubMed1987

Influence of dietary fat on menstrual cycle and menses length.

Menstrual cycle and menses lengths were determined in 31 healthy premenopausal women randomized into one of two sets of weight-maintaining diets, those with a ratio of polyunsaturated to saturated fatty acids (P/S ratio) of 1.0 and those with a P/S ratio of 0.3. After a baseline interval of one menstrual cycle, both groups were fed a high fat diet (40 per cent energy from fat) for four menstrual cycles per subject, followed by a similar interval on a low fat diet (20 per cent energy from fat). There was a significant increase of 1.3 d (P = 0.02) in the average menstrual cycle length and 0.5 d (P = 0.01) in menses length on the low fat diet. Although no significant differences were evident between the P/S groups, the effect of low fat on menstrual cycle and menses length was most pronounced in the P/S = 1.0 group.

Adult↗

PubMed1986

Effects of low fat diets varying in P/S ratio on nutrient intakes, fecal excretion, blood chemistry profiles, and fatty acids of adult men.

Twenty-three apparently healthy volunteers aged 35 to 60 years consumed closely monitored self-selected (SS) diets for five weeks followed by two low fat controlled diets (25% energy) for two six-week periods followed by another five-week SS diet. The two low fat diets, fed in a crossover design to one-half of the subjects per controlled diet period, had a polyunsaturated/saturated (P/S) fat ratio of either 0.3 or 1.0. Results are reported for bi-weekly measurements of energy and nutrients; blood profiles and plasma fatty acids; and for end-of-period values for stool characteristics. Blood chemistry profiles differed in the two groups. The low P/S diet produced significant increases not only in cholesterol, but in 16:0, 16:1, and percent saturated fatty acids and decreases in 18:2 and omega 6 fatty acids. The reverse was seen with the high P/S diet. The essential fatty acid (EFA) linoleic acid returned in the poststudy period to prestudy levels (all subjects), but arachidonic acid did not. The explanation for negative correlation between magnesium intake or excretion and percent plasma linoleic acid must await further research.

Adult↗

PubMed1986

Self-selected vs. controlled diet as a baseline for human studies: effects of nutrient intakes on blood pressure and on constituents of blood and urine.

This study demonstrates that a three-week stabilization period, in which all subjects eat an identical diet, produced a more uniform but different baseline of metabolic parameters than the subject's self-selected or "habitual" diets. Subjects required more food energy to maintain initial body weights during the stabilization period than when they ate their reported self-selected diets; average intakes of almost all nutrients were higher from the stabilization than from the self-selected diet. The switch to the stabilization diet produced small but significant reductions in blood pressure, in some serum enzymes, urine volume, and sodium; and statistically significant increases in serum LDL cholesterol, potassium, aldosterone, protein, albumin, phosphorus, BUN, and in urine potassium. The findings indicate that results must be interpreted with caution from studies in which the baseline for measuring metabolic variables is established by feeding subjects a standardized diet that differed markedly from their regular, self-selected diets.

Adult↗

PubMed1986

Vitamin E in foods from high and low linoleic acid diets.

As part of a human diet study, vitamin E activity was estimated in foods used in seven daily menus. Each menu was designed to contain 35% fat calories with either 10 or 30 gm/day of linoleic acid (18:2) and 500 mg/day of cholesterol. To estimate vitamin E activity, each food used in the menus was analyzed for alpha and gamma tocopherol content by high-pressure liquid chromatography with fluorescence detection. This article reports the alpha and gamma tocopherol contents of those foods, tocopherol contributions from each food in one sample 2,400-kcal menu, and the mean daily vitamin E activity (milligram alpha tocopherol equivalents) of all seven menus at five caloric levels. Major sources of alpha tocopherol (greater than 10% of the RDA) common to both diets (10 and 30 gm linoleic acid) were olive oil and a few fruits and vegetables. Additional major sources in the 30-gm linoleic acid diets were polyunsaturated fatty acid (PUFA) vegetable oils and margarine. Contrary to a common assumption, increasing the level of PUFA in the menus did not necessarily result in higher milligram equivalents of alpha tocopherol because soybean oil, with a tocopherol composition that is predominantly gamma tocopherol, was the major source of linoleic acid in the diets. Thus, vitamin E activity was not necessarily increased when soybean oil was substituted for a less saturated fat such as olive oil, which has mostly alpha tocopherol.

Chromatography, High Pressure Liquid↗

PubMed1985

Moderate changes in linoleate intake do not influence the systemic production of E prostaglandins.

A pilot study was undertaken to determine if moderate changes in linoleate (18:2 omega 6) intake would modulate the prostaglandin E turnover concurrently with, or independently of, changes in the plasma prostaglandin (PG) precursor levels. Four adult male volunteers in good health were fed two controlled diets containing 35% of energy from fat, with either 10 (diet L) or 30 g (diet H) linoleate/day, 30 to 50 g saturated fatty acids/day, and the balance mainly monounsaturated fatty acids. All four subjects were consuming sufficient amounts of polyunsaturates before the study. Protein (13-14%) and carbohydrate (51-53%) contribution to total caloric intake was kept constant. The menu cycle was 7 days, and all diets were calculated to provide adequate amounts of nutrients known to be required by man when data were available. Plasma fatty acids were determined by gas-liquid chromatography, and the turnover of E prostaglandins was assessed by measuring the urinary output of the major metabolite of PGE1 + PGE2 (PGE-M). Whereas we found a clear correlation between 18:2 omega 6 intake and 18:2 omega 6 concentrations in the neutral lipid (P = 0.007) and phosphoglyceride (P = 0.012) fractions of plasma, arachidonate (20:4 omega 6) concentrations in those same plasma fractions did not respond significantly to changes in linoleate intake. Moreover, we could not detect an influence of moderate changes in dietary levels of 18:2 omega 6 on the systemic production of PGE as measured by the daily urinary output of PGE-M.

Adult↗

PubMed1984

Evaluation of long-term dietary intakes of adults consuming self-selected diets.

Mean daily intakes of calories and 19 nutrients were calculated for 13 males and 16 females, ages 20 to 53 yr, who kept daily diet records for 1 yr. Mean daily caloric and 19 selected nutrient intakes of the subjects met or exceeded the 1980 recommended dietary allowances except for iron and calcium for females. Males had higher intakes than females for all nutrients studied except crude fiber, vitamin A, and vitamin C. However, nutrient density values were comparable for both sexes, except that the females had higher nutrient density values for vitamin A than did the males. The younger subjects had higher intakes of calories and saturated fat than the older ones. The younger males had higher intakes of total fat, saturated fat, and oleic acid than the older males. The consistency of reporting food intakes examined by applying a systematic sampling method designed for this study did not vary considerably when diet records kept over a long period of time were evaluated by four methods.

Adult↗

PubMed1984

Effect of making duplicate food collections on nutrient intakes calculated from diet records.

In a 1-yr study in which food intakes were recorded daily, subjects were asked to make duplicate food collections for 1 wk during each of the four seasons. Mean calculated energy intake of the 29 subjects was 12.9% less during the food collection periods than the mean for the entire year (which included collection periods). There were also significant reductions in the reported intake of all nutrients during the collection periods. Protein, vitamin A, saturated fat, and cholesterol intakes were decreased to the greatest extent. The actual decrease in energy intake was greater for the males than for the females, but the percentage was the same (12.9%). The younger group of subjects (less than or equal to 35) decreased energy intake 16.8% and the older group (greater than 35) 8.8%. Comparison of intakes during collection periods with intakes the week before and the week after showed that 28 of the 29 subjects decreased their energy intake from 1.1 to 32.3%. These data suggest that intakes of subjects during food collection periods do not represent their habitual levels of intake reported throughout the year.

Adult↗