Life Cycle Nutrition: Pregnancy PDF

Life Cycle Nutrition: Pregnancy Introduction to Human Nutrition Faculty of Science Department of Biochemistry Basic Physiology of Pregnancy The Placenta: 3 main functions ‐ gas exchange, waste removal, nutrient exchange A...

Life Cycle Nutrition: Pregnancy Introduction to Human Nutrition Faculty of Science Department of Biochemistry Basic Physiology of Pregnancy The Placenta: 3 main functions ‐ gas exchange, waste removal, nutrient exchange Adequate nutritional status prior to conception is necessary to support implantation in the uterus, and to support early placental growth Faculty of Science Department of Biochemistry Organs develop at different times during the gestation period Inadequate nutrient availability during CRITICAL periods of fetal growth may terminate the pregnancy, or alter organ development, affecting the lifetime health status of the fetus Faculty of Science Department of Biochemistry Example of the Critical Window ‐ Folate availability and neural tube defects (spina bifida) Well characterized example of nutrient deficiency during a critical window of development Neural tube closure occurs before the 6th week of gestation Directly linked to folate deficiency Rates of NTD pre‐ versus post‐folic acid fortification: Canada – 46% decline (1.58 → 0.86 per 1000 births) NL – ~85% decline (4.56 → 0.76 per 1000 births) De Wals et al. N Engl J Med 2007; 357:135‐142 Faculty of Science Department of Biochemistry Body Weight & Weight Gain in Pregnancy Ideally, women should have a healthy weight before pregnancy Low or high pre‐pregnancy body weight is associated with higher adverse outcomes 1st trimester – 1.5 kg (3.5 lbs) total 2nd and 3rd trimesters – 0.5 kg (1 lb) per week Components of weight gain varies by stage of gestation Ideal weight gain in a normal weight woman is 11.5 – 16 kg (25‐ 35 lbs) ~40 weeks divided into 3 gestational stages Faculty of Science Department of Biochemistry Maternal Gestational Weight Gain (GWG) Distribution of pre‐pregnancy BMI in Canada 34% of pregnancies were complicated by excess maternal body weight Public Health Agency of Canada's 2005‐2006 Maternity Experiences Survey (MES) Faculty of Science Department of Biochemistry Gestational Weight Gain (GWG) Distribution of gestational weight gain Excess body weight, or excess GWG increases the number of caesarean births Public Health Agency of Canada's 2005‐2006 Maternity Experiences Survey (MES) Faculty of Science Department of Biochemistry Contribution of Pre‐pregnant Body Weight and Gestational Weight Gain (GWG) to Infant Outcomes Preterm Birth Risks Associated with preterm or low birth weight: Short term: higher mortality rates in year 1 of life (< 5.5 lbs, 40x more likely to die before 1 yr) Long term: increased risk of childhood and adult obesity, Type 2 diabetes, CVD (fetal programming theory), poorer school outcomes, lower adult IQ, Large for Gestational Age (LGA) Risks Associated with high birth weight (LGA): Complications during birthing process Increased risk of childhood and adult obesity Public Health Agency of Canada's 2005‐2006 Maternity Experiences Survey (MES) Faculty of Science | Department of Biochemistry Risks Associated with Obesity in Pregnancy High risk of complications for the mother during pregnancy Hypertension, gestational diabetes, caesarean section, post‐ op/post delivery infections High risk of adverse outcomes for the infant 2x the risk of neural tube defects Greater rate of heart defects Higher risk of preterm birth Risk of high body weight at birth Faculty of Science | Department of Biochemistry Body Weight, GWG and other Factors Contributing to Infant Birth Weight Low birth weight may be caused by: Low maternal body weight, inadequate GWG or both Smoking during pregnancy* Poor maternal nutrition Maternal alcohol intake Maternal diseases (ie uncontrolled blood pressure) Heredity Faculty of Science | Department of Biochemistry Global Concerns of Maternal Body Weight and GWG Maternal Underweight + Malnutrition Global Infant Mortality Rates 2016 4.6 per 1000 Infants born underweight, with nutritional deficiencies 5.8 per 1000 2.0 per 1000 Underlies > 3 million deaths per year of children under 5 yrs of age ~ 45 percent of all deaths in this age group attributed to low birth weight + nutrient Afghanistan: 113 per 1000 deficiencies + inadequate breast feeding Liu L, Johnson H L, Cousens S, Perin J, Scott S., and others. 2012. “Global, Regional, and National Causes of Child Mortality: An Updated Systematic Analysis for 2010 with Time Trends Since 2000.” The Lancet 379 (9832): 2151–61. http://world.bymap.org/InfantMortality.html Faculty of Science | Department of Biochemistry Nutritional Needs During Pregnancy Additional Energy (Calorie) Requirements: 1st Trimester – no additional energy (Calories) but choosing nutrient dense foods is very important 2nd Trimester – additional 340 kcal/day 3rd Trimester – additional 450 kcal/day Faculty of Science | Department of Biochemistry Nutritional Needs During Pregnancy Additional Protein Requirements: DRI recommends an additional 25 g per day (over the RDA of 0.8 g/kg/d) ie. 60 kg woman (~130 lbs) should consume 0.8 x 60 kg = 48 g + 25 g = 73 g protein/d Not usually a concern with a standard Western diet (we eat 1.5‐2x already) It is a concern for vegans – may be difficult to increase energy and protein intake to meet pregnancy needs High intake of legumes, tofu, nuts, seeds and whole grains is essential Faculty of Science | Department of Biochemistry Nutritional Needs During Pregnancy Dietary Fat Intake: Fat intake may contribute to excessive GWG, but fatty acids are important for fetal development Brain development requires high amounts of DHA (n‐3) and arachidonic acid (n‐6) Fish/seafood intake is recommended (150‐340 g/week) – but concern about environmental contaminants (ie methyl mercury)? Okay ‐ Salmon, trout, herring, haddock, canned light tuna (not white Albacore), pollock, sole, flounder, mackerel Caution! tuna (fresh and frozen), shark, swordfish, marlin, orange roughy (limit to less than 150 g/month) The value of fish oil supplementation in pregnancy remains controversial for both the developing infant and the mother Faculty of Science Department of Biochemistry https://www.fda.gov/news‐events/press‐announcements/fda‐and‐epa‐issue‐final‐fish‐ consumption‐advice Faculty of Science | Department of Biochemistry Nutritional Needs During Pregnancy Folate and vitamin B12: Both are needed in large amounts in pregnancy to support cell proliferation RDA for folate = 600 µg/d (women capable of becoming pregnant should take 400 µg/d on top of food sources) High folate intake (> 1 mg/d) can mask B12 deficiency (UL for folate = 1 mg/d) Risk for B12 deficiency in vegans – supplementation is required Calcium (Ca) Needed for skeletal growth and tooth development RDA for Ca (1000 mg/d) is the same for pregnant and non‐preg women! (not so for teenage pregnancy) Maternal skeleton serves as a source of calcium for fetal growth, particularly in late pregnancy (300 mg/d transferred to fetus) Efficiency of calcium absorption in the GI tract DOUBLES in early pregnancy, to prepare for the fetal req’t later—will use bone Ca regardless of accretion Faculty of Science | Department of Biochemistry Nutritional Needs During Pregnancy Iron in Pregnancy Cessation of menstruation helps conserve maternal iron Iron absorption from the GI tract increases efficiency up to 3x Maternal demand for iron is high to satisfy increasing blood volume during pregnancy Fetus has high iron demands for blood formation, and for iron stores to last until ~ 6 mo of age Fetal iron demands take priority over maternal iron status RDA for iron is 27 mg/d (compared to 18 mg/d for non‐ pregnant women) Iron supplements recommended for 2nd and 3rd trimesters Faculty of Science Department of Biochemistry Summary of Supplement Use in Pregnancy Folate and iron routinely Multivitamins if evidence of a poor diet, or high risk group such as: – Adolescent pregnancy – Multiple fetuses – Smoking, alcohol or drug use Faculty of Science | Department of Biochemistry General Diet/Food Advice For Pregnancy Limit caffeine intake to < 300 mg/d (2 cups of coffee, ~ 6 cups of tea is limit, but half that often recommended) Avoid uncooked animal protein Smoked fish, raw sushi, raw eggs, raw meat (tartar style…) Cautious use of non‐nutritive sweeteners (sugar substitutes) Avoid dieting, esp fad diets Avoid vitamin/mineral mega dose supplements Pregnancy increases the risk for the foodborne illness – “listeriosis” which can severely affect the health of the fetus Found in meat and dairy especially See ways to protect from listeriosis on page 598 of textbook (not required) Faculty of Science | Department of Biochemistry Alcohol and Fetal Growth Alcohol can damage the ovum or sperm, contributing to abnormal fetal development or pregnancy failure Exposure to alcohol can restrict oxygen and nutrient delivery to the fetus, which quickly affects brain development halt delivery of O2 through the umbilical cord with sudden exposure Slow cell division, affecting organ growth (esp brain) and normal development “critical window” Faculty of Science | Department of Biochemistry Alcohol and Pregnancy Fetal Alcohol Syndrome (FAS)/Fetal Alcohol Spectrum Disorder (FASD) Drinking alcohol during pregnancy threatens the fetus with a cluster of symptoms that may include: Irreversible brain damage Growth delay Mental retardation Facial abnormalities Vision abnormalities Defects in organ development/function Affects almost 1% of pregnancies in Canada Alcohol‐related neurodevelopmental disorder (ARND) and AR birth defects (ARBD) More subtle consequences of fetal alcohol exposure, and may cause mood disorders, poor social skills, aggression, behavioural disorders, physical deformities, greater risk for addiction to drug/alcohol Faculty of Science Department of Biochemistry Faculty of Science | Department of Biochemistry To Drink or Not to Drink….. A significant proportion of Canadian women continue to drink during pregnancy ~ 5% drink frequently or binge drink 12% report drinking at some point during pregnancy Drinking before being aware of the pregnancy is common High risk of spontaneous abortions and still births with 5 or more drinks/wk FAS reported with only 2 drinks per day Associations between ARND or ARBD and level of alcohol intake is not known Alcohol intake in early pregnancy is likely more detrimental Health Canada and the Canadian Pediatric Society recommend abstaining from alcohol prior to becoming pregnant, and abstain totally during pregnancy. If drinking during pregnancy, stop immediately. Faculty of Science Department of Biochemistry To Drink or Not to Drink…..for the guys Faculty of Science Department of Biochemistry Exercise During Pregnancy?  physical activity/low impact sports best Facilitates labor/ reduces discomfort in pregnancy Reduces psychological stress, prevents Gest Diab Prior to starting, consult MD