hun 3403 wk1 d2 chapter 2 preconception nutrition
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Chapter Introduction Adequate health & nutrition status are needed for successful reproduction Inadequate health & nutrition status may disrupt reproductive capacityTRANSCRIPT
HUN 3403 Wk1 D2 Chapter 2 Preconception Nutrition Chapter
Introduction Adequate health & nutrition status are needed for
successful reproduction Inadequate health & nutrition status
may disrupt reproductive capacity Preconception Overview:
Infertility
~15% of couples are infertile 44% of couples diagnosed as infertile
will eventually conceive without use of technology Healthy couples
have a 20% to 25% chance of conception within a given menstrual
cycle Preconception Overview: Miscarriage
Miscarriage: Loss of conceptus in 1st 20 weeks of pregnancy Causes
of miscarriages: Defect in fetus Maternal infection Structural
abnormalities of uterus Endocrine or immunological disturbances
Preconception Overview: Subfertility
Subfertility: Reduced level of fertility characterized by unusually
long time for conception ~18% of couples are subfertile Examples:
Having multiple miscarriages Sperm abnormalities Infrequent
ovulation 2020 Nutrition Objectives for the Nation Related to
Preconception Reproductive Physiology
Key Terms: Pubertyperiod in which humans become biologically
capable of reproduction Ovaeggs females produce & store within
the ovaries Menstrual Cycle ~4 week interval in which hormones
direct buildup of blood & nutrient stores within uterus; ovum
matures & is released Reproductive Physiology
Development of female & male reproductive systems Begins during
first months after conception & Continue to grow & develop
through puberty Capacity for reproduction Establishes during
puberty when hormonal changes stimulate maturation of reproductive
system Reproductive Physiology: Ova and Women
Women born with life-time supply of ~7 million immature ova ~ ova
will mature & be released during fertile years Quality of eggs
decrease with age due to damage of cells DNA Reproductive
Physiology: Sperm and Men
Sperm production begins during puberty, decreases somewhat after
age 35 with production continuing to old age Female Reproductive
System Male Reproductive System Hormonal Effects During the
Menstrual Cycle
Gonadotropin-releasing hormone (GnRH) Stimulates pituitary to
release FSH and LH Follicle-stimulating hormone (FSH) Stimulates
maturation of ovum & sperm,production of estrogen Luteinizing
hormone (LH) Stimulates secretion of progesterone and testosterone
Hormonal Effects During the Menstrual Cycle
Estrogen Stimulates release of GnRH in follicular phase &
follicle growth & maturation of follicle Stimulates vascularity
& storage of glycogen & other nutrients within uterus
Progesterone Prepares uterus for fertilized ovum, increases
vascularity of endometrium, & stimulates cell division of
fertilized ova Two Phases of Menstrual Cycle
Follicular Phase(first half of menstrual cycle) Follicle growth
& maturation Main hormones: GnRH, FSH, estrogen, &
progesterone Luteal Phase(last half of menstrual cycle) After
ovulation Formation of corpus luteum in estrogen & progesterone
stimulate menstrual flow Postaglandins & cramps Changes in the
Ovary and Uterus Male Reproductive System
Interactions among hypothalamus, pituitary gland, and testes
Process is ongoing rather than cyclic Androgens Testosterone Sperm
are stored in the epididymis & released in semen Sources of
Disruptions in Fertility
Adverse nutritional exposure Contraceptive use Severe stress
Infection Tubal damage or other structural damage Chromosomal
damage Factors Related to Altered Fertility Nutrition-Related
Disruptions in Fertility
Undernutrition Weight loss Obesity High exercise levels Intake of
specific foods & food components Undernutrition and
Fertility
Undernutrition in women previously well-nourished Associated with a
dramatic decline in fertility that recovers when food intake does
Food shortages in countries have been accompanied by dramatic
declines in birth rates Body Fat and Fertility Decreased fertility
seen with low or high body fat due to alterations in hormones
Estrogen & leptin Levels increased with high body fat &
reduced with low body fat Both extremes lower fertility Infertility
lower with BMI 30 Weight Loss and Fertility in Females
Weight loss >10-15% of usual weight decreases estrogen, LH, FSH
Results in amenorrhea, anovulatory cycles, & short or absent
luteal phases Treatment with fertility drug Clomid not effective in
underweight women Weight Loss and Fertility in Males
Studies from World War II showed 50% decrease in malefertility
during starvation Sperm viability & motility decrease with wt.
10 to 15% below normal & cease at wt. loss exceeding 25% of
normal Oxidative Stress, Antioxidant Status, and Fertility
Oxidative stress in men Decreases sperm motility Reduces ability of
sperm to fuse with an egg Oxidative stress in women Harm egg and
follicular development Interfere with corpus luteum function
Interfere with implantation of the egg Oxidative Stress,
Antioxidant Status, and Fertility
Vitamin E Vitamin C Beta-carotene Selenium Found in vegetables and
fruits. Protect cells of the reproductive system, including eggs
and sperm Oxidative Stress, Antioxidant Status, and Fertility
Zinc status and Fertility in Men Plays important roles In the
reduction of oxidative stress In sperm maturation In testosterone
synthesis Has been investigated for potential role in infertility
Plant Foods and Fertility
Low-fat, high fiber linked to irregular menstrual cycles
Isoflavones (from soy) decrease levels of estradiol, progesterone,
LH Also related to reduced sperm count in men Folate Status and
Fertility
Intake by women of multivitamins with folate associated with
decline in ovulatory infertility Intake by men of multivitamins
with folate associated with improved sperm counts, motility,
decreased abnormal forms of sperm Iron Status and Fertility
Rate of infertility lower in women who use iron supplements or iron
from plant foods 14% of U.S. women enter pregnancy with inadequate
iron stores Caffeine and Fertility
Study results are mixed on effects of caffeine Some studies have
shown increased time to conception, others have failed to find
effects If individuals choose to cut back on caffeinated beverages,
it is their choice Alcohol and Fertility Alcohol may decrease
estrogen & testosterone levels or disrupt menstrual cycles
Studies on weekly drinks consumed show: 1-5 drinks 39% in
conception >10 drinks 66% in conception Heavy-Metal Exposure and
Fertility
High lead levels decreased sperm production, abnormal motility,
shape Build-up of cadmium, molybdenum, manganese, boron, and other
metals also affect male fertility Exercise and Fertility
Adverse effects of intense physical activity Delayed age at puberty
Lack of menstrual cycles Appear to result from hormonal and
metabolic changes Related to caloric deficits Reduced levels of
estrogen Low levels of body fat Decreased bone density Nutrition
During the Periconceptual Period
Very-early-pregnancy nutrition exposures Folate status prior to
conception Neural tube defects Iron status prior to conception Iron
deficiency is most common deficiency worldwide Recommended dietary
intakes for preconceptional women Nutritional Disruptions MyPlate
Recommendations for Preconceptional Women Example Menu for
Preconceptional Women Nutritional Side Effects of Hormonal
Contraception
Progestin only weight gain, decreased bone mineral accretion
Combination contraceptives altered bloodlipid levels, increased
blood and insulin levels, increased stroke Model Preconceptional
Nutrition Programs
Preconceptional benefits of WIC Decreasing iron deficiency in
preconceptional women in Indonesia Preconception Care: Preparing
for Pregnancy
CDCs Preconception Health Initiative Recommends that primary health
care visits include: Preconception health & pregnancy outcome
education Screening for vaccination, weight, iron & folate
status Assessment of alcohol use Management of diabetes &
celiac disease Nutrition Care Process
Nutrition care standards developed by the Academy of Nutrition and
Dietetics Part of new technology-based systems To facilitate
health-services delivery Cost evaluation Electronic charting Coding
and outcome measurement Nutrition Care Process
The Nutrition Care Process Step 1: Nutrition assessment Step 2:
Nutrition diagnosis Step 3: Nutrition intervention Step 4:
Nutrition monitoring and evaluation See Table 2.9 for summary