Prior research has shown adult diets rich in omega-3 long-chain polyunsaturated fatty acids (omega-3 LC-PUFAs) can improve adult metabolic health. Previous studies have also shown maternal overnutrition during pregnancy/lactation adversely affects metabolic functioning in adult offspring. The purpose of the current study was to investigate the interaction of these two metabolism regulating factors by assessing the effectiveness of a postweaning diet rich in omega-3 long chain-polyunsaturated fatty acids (omega-3 LC-PUFAs) to improve metabolic function in adult offspring whose mothers were fed a high-saturated fat “Western” diet during pregnancy/lactation. We compared metabolic function between offspring of three prenatal-lactation/postweaning diet lines of Sprague-Dawley rats: 1) offspring of mothers fed a high-saturated fat “Western” diet during pregnancy-lactation, then weaned to a high omega-3 LC-PUFA diet (Western/PUFA); 2) offspring of mothers fed a control diet during pregnancy-lactation, then weaned to a high omega-3 LC-PUFA diet (Control/PUFA); and 3) offspring of mothers fed a Western diet during pregnancylactation, and postweaning (Western/Western). Fasting plasma insulin, triglycerides, and insulin resistance (HOMA-IR) of Western/PUFA animals were intermediate to those of Western/Western and Control/PUFA offspring, although these differences did not reach statistical significance. This suggests the metabolic benefits of an omega-3 LC-PUFA-rich diet are insufficient to overcome the deleterious effects of a high-saturated fat prenatal-lactation diet.
The health benefits associated with a diet rich in omega-3 fatty acids, and/or a low omega-6:omega-3 ratio, have been reported in a large number of epidemiological and clinical studies. The cardiometabolic benefits associated with these diets include reduced insulin resistance, improved blood lipid profiles, lowered blood pressure and decreased incidence of type 2 diabetes and metabolic syndrome [
Epidemiological and experimental animal research has also shown maternal overnutrition during pregnancy and lactation, especially via a high energy, high-saturated fat, low fiber “Western” diet, deleteriously alters metabolic function in adult offspring, even when animals are weaned onto control diets [
Sprague-Dawley male and female adult breeding animals were acquired from Simonsen Laboratories, Inc., and housed at the University of Nevada Las Vegas Animal Care Facility. During a 10-day acclimatization period, male and female animals were kept in separate plastic cages and fed a standard chow diet (
F0 Generation | F1 Generation |
---|---|
Maternal Diets | Post-weaning Diets |
Control | PUFA |
Western | PUFA |
Western | Western |
Component | Control | PUFA | Western |
---|---|---|---|
Calories provided by | |||
Protein | 28.5% | 30.3% | 17.8% |
Fat | 13.5% | 59.8% | 29.8% |
Carbohydrate | 58.0% | 10.0% | 52.3% |
P:S | 1:1 | 2:1 | 0.5:1 |
Omega-6:Omega-3 | 6.5:1 | 1.5:1 | 9:1 |
approximately 1 cm of the end of the tail. Approximately 2 mm of the tip of the tail was excised with a surgical scalpel, and blood was collected by milking the tail. Heparin coated capillary tubes were used to collect approximately 100 μl of blood for glucose and blood lipid analyses. In addition, 600 μl of blood was collected in non-heparin capillary tubes for insulin analysis. These samples were spun at 4000 g at 4˚C, after which the plasma was removed from the samples and stored in cryogenic vials at −40˚C until insulin analysis was performed. The study was approved by the UNLV Institutional Animal Care and Use Committee (IACUC).
Study diets varied in terms of macronutrients, sources of fat and polyunsaturated to saturated fatty acid ratios (
Analysis of plasma blood glucose and lipids were performed using the Abaxis Blood Chemistry Analyzer. Glycosylated hemoglobin (HbA1c) was measured using the Bayer DCA 200 Chemistry Analyzer. Insulin was analyzed via ELISA by ZRT Laboratories in Beaverton, Oregon.
The three groups are not independent of each other given that the Western/PUFA animals shared maternal diet with the Western/Western animals and postweaning diet with the Control/PUFA animals. As a result, Mann- Whitney U tests were used to examine differences in body weight/BMI, HbA1c, fasting plasma glucose, HOMA- IR, fasting plasma insulin, and triglycerides among the three experimental diet groups. For body weight data, given a larger sample size, 2 sample t-tests were used to examine differences in body weight among pre-wean- ing pups after data normality was confirmed. Levene’s tests were performed to examine the homogeneity of variances. Data were analyzed using SPSS version 21.0 (IBM Corp., Armonk, NY). Descriptive statistics were used to detect potential outliers of which values were greater or less than mean ±1.65 standard deviations. The significance level was fixed at 0.05 for all statistical tests.
Mean fasting glucose was lower among Western/Western animals than both Control/PUFA and Western/PUFA offspring, although these differences were not statistically significant. Mean HbA1c values varied minimally among Control/PUFA, Western/PUFA and Western/Western animals and did not reach statistical significance.
Mean fasting insulin and HOMA-IR values of Western/PUFA animals were intermediate to those of Western/ Western and Control/PUFA offspring. While mean plasma insulin was 23% lower, and mean HOMA-IR was 10%
Biomarker | Control/PUFA | Western/PUFA | Western/Western | |||
---|---|---|---|---|---|---|
N | Mean ± S.E. | N | Mean ± S.E. | N | Mean ± S.E. | |
BMI (g/cm2) | 5 | 0.60 ± 0.02 | 4 | 0.61 ± 0.04 | 3 | 0.60 ± 0.04 |
Male | 3 | 0.62 ± 0.02 | 2 | 0.68 ± 0.01 | 2 | 0.65 ± 0.01 |
Female | 2 | 0.57 ± 0.02 | 2 | 0.55 ± 0.02 | 1 | 0.52 ± 0.00 |
HbA1c (%) | 5 | 3.38 ± 0.09 | 4 | 3.35 ± 0.03 | 3 | 3.37 ± 0.03 |
Male | 3 | 3.50 ± 0.06 | 2 | 3.35 ± 0.05 | 2 | 3.40 ± 0.00 |
Female | 2 | 3.20 ± 0.10 | 2 | 3.35 ± 0.05 | 1 | 3.30 ± 0.00 |
Glucose (mmol/L) | 5 | 8.57 ± 0.45 | 4 | 8.61 ± 0.34 | 3 | 7.48 ± 0.27 |
Male | 3 | 8.63 ± 0.75 | 2 | 8.92 ± 0.08 | 2 | 7.75 ± 0.03 |
Female | 2 | 8.47 ± 0.58 | 2 | 8.31 ± 0.69 | 1 | 6.94 ± 0.00 |
HOMA-IR | 5 | 1.09 ± 0.06 | 4 | 1.86 ± 0.45 | 3 | 2.07 ± 0.20 |
Male | 3 | 1.17 ± 0.02 | 2 | 1.78 ± 0.22 | 2 | 2.27 ± 0.01 |
Female | 2 | 0.97 ± 0007 | 2 | 1.95 ± 1.08 | 1 | 1.67 ± 0.00 |
Insulin (pmol/L) | 5 | 20.05 ± 1.39 | 4 | 33.18 ± 7.34 | 3 | 42.97 ± 2.76 |
Male | 3 | 21.54 ± 1.91 | 2 | 31.14 ± 3.50 | 2 | 45.72 ± 0.42 |
Female | 2 | 17.82 ± 0.00 | 2 | 35.22 ± 17.40 | 1 | 37.47 ± 0.00 |
Triglycerides (mmol/L) | 5 | 0.66 ± 0.09 | 4 | 0.58 ± 0.03 | 3 | 0.83 ± 0.16 |
Male | 3 | 0.70 ± 1.16 | 2 | 0.55 ± 0.04 | 2 | 0.86 ± 0.28 |
Female | 2 | 0.60 ± 0.08 | 2 | 0.62 ± 0.05 | 1 | 0.76 ± 0.00 |
Biomarker | Group Comparison | P-value |
---|---|---|
BMI (g/cm2) | Control/PUFA & Western/PUFA Western/PUFA & Western/Western Control/PUFA & Western/Western | 0.905 0.629 0.786 |
HbA1c (%) | Control/PUFA & Western/PUFA Western/PUFA & Western/Western Control/PUFA & Western/Western | 1.000 0.229 0.143 |
Fasting Glucose (mmol/L) | Control/PUFA & Western/PUFA Western/PUFA & Western/Western Control/PUFA & Western/Western | 0.730 0.857 0.786 |
HOMA-IR | Control/PUFA & Western/PUFA Western/PUFA & Western/Western Control/PUFA & Western/Western | 0.286 0.629 0.036 |
Fasting Insulin (pmol/L) | Control/PUFA & Western/PUFA Western/PUFA & Western/Western Control/PUFA & Western/Western | 0.111 0.400 0.036 |
Triglycerides (mmol/L) | Control/PUFA & Western/PUFA Western/PUFA & Western/Western Control/PUFA & Western/Western | 0.556 0.114 0.393 |
lower among Western/PUFA animals than Western/Western offspring, these differences did not reach statistical significance. By contrast, Western/Western animals had significantly higher fasting plasma insulin (P < 0.05), and were significantly more insulin resistant (P < 0.05) than animals weaned to the PUFA diet, but whose mothers consumed the control diet during pregnancy-lactation (Control/PUFA) (
The largest difference in mean fasting triglycerides between diet groups was the 30% higher value of Western/ Western animals compared to Western/PUFA offspring (0.58 mmol/L). Mean triglycerides levels of Control/ PUFA animals (0.66 mmol/L) were intermediate to those of Western/Western and Western/PUFA offspring. None of these differences, however, reached statistical significance.
There were no significant differences in body weights on day 7 among offspring whose mother consumed the Western or Control diets during pregnancy-lactation. By day 21 (weaning), however, offspring of mothers fed the Western diet during pregnancy-lactation were significantly (P < 0.01) higher.
Western/Western offspring maintained the highest body weights throughout the study (after weaning), weigh- ing 31 grams more, on average, than Western/PUFA animals, and 15 grams more than Control/PUFA offspring on day 120 (
Day | Control | Western | P-value* | ||
---|---|---|---|---|---|
N | Mean ± S.E. | N | Mean ± S.E. | ||
7 | 18 | 17.20 ± 0.19 | 18 | 16.44 ± 0.48 | 0.153 |
21 | 18 | 47.93 ± 0.61 | 18 | 51.64 ± 0.72 | 0.000 |
*2 sample t-test.
Day | Control/PUFA | Western/PUFA | Western/Western | |||
---|---|---|---|---|---|---|
N | Mean ± S.E. | N | Mean ± S.E. | N | Mean ± S.E. | |
25 | 5 | 64.54 ± 0.91 | 4 | 66.95 ± 2.34 | 3 | 69.83 ± 4.83 |
49 | 5 | 180.44 ± 6.80 | 4 | 184.33 ± 8.49 | 3 | 217.47 ± 26.23 |
63 | 5 | 257.34 ± 23.10 | 4 | 232.85 ± 17.88 | 3 | 277.63 ± 42.37 |
70 | 5 | 278.22 ± 22.16 | 4 | 255.10 ± 23.18 | 3 | 296.83 ± 45.07 |
81 | 5 | 302.62 ± 27.59 | 4 | 283.50 ± 25.28 | 3 | 321.80 ± 45.95 |
109 | 5 | 341.48 ± 32.99 | 4 | 328.88 ± 33.80 | 3 | 370.57 ± 42.75 |
120 | 5 | 355.50 ± 30.60 | 4 | 339.78 ± 32.83 | 3 | 370.93 ± 48.41 |
Previous experimental animal studies have shown that the adult offspring of mothers who consume a diet in high-saturated fat during pregnancy and lactation and are then weaned to a control diet have high levels of fasting insulin, are insulin resistant, and obese [
The size of our pilot study is a significant limitation, and consequently, our results should be interpreted with caution. If confirmed by additional research, however, our results may have important implications for the content and timing of potential future diet-based interventions aimed at type 2 diabetes/Metabolic Syndrome prevention and treatment. The results presented here are consistent with a large body of experimental animal, clinical and epidemiological studies on the developmental origins of obesity related health disorders. Our findings suggest that while interventions aimed at increasing intake of omega-3 LC-PUFAs in adulthood can improve biomarkers of metabolic health, the deleterious effects of a poor (e.g., high energy, low fiber, high-saturated fat) maternal diet during pregnancy and lactation limit the effectiveness of such an intervention. As a result, future prevention efforts may be most effective by complementing adult dietary interventions with longer term, multi-generation prevention strategies that aim to optimize maternal and child health by improving maternal health and nutrition before pregnancy.
The authors would like to acknowledge the funding support provided by the UNLV Edwards and Olswang and the Rocchio research grants. We would also like to acknowledge the helpful contributions of Alyssa Crittenden and Celeste Giordano.