Plant-Based Diets and Gestational Diabetes
Plant-Based Diets and Gestational Diabetes
Learn about the challenges
patients face and strategies to ensure they get the nutrients they need for a
healthy pregnancy and baby.
Eight months before Paula became pregnant,
she decided to become a vegetarian. She was 70 lbs overweight and believed that
cutting out red meat, poultry, and fish, and eating only plant-based foods
would help her lose weight and obtain better health.
When Paula was diagnosed with gestational
diabetes mellitus (GDM) in her 26th week of pregnancy, she continued eating a
vegetarian diet to increase her chances of having a healthy pregnancy and baby.
Emerging research continues to show the
benefits of plant-based diets in the prevention and management of chronic
disease. The Academy of Nutrition and Dietetics
(the Academy) and other
healthcare organizations state that a plant-based diet, including a
well-planned vegetarian diet, is appropriate for individuals during all stages
of the life cycle, including pregnancy.
Studies indicate vegetarians have lower
LDL cholesterol levels and blood pressure, and decreased rates of hypertension
and type 2 diabetes than nonvegetarians.1 Plant-based diets tend to be higher
in whole grains, legumes, nuts, fruits, and vegetables—foods that are rich in
dietary fiber, magnesium, potassium, vitamins C and E, folate, carotenoids,
flavonoids, and other phytochemicals associated with low disease risk.
However, when pregnant women, especially
those diagnosed with GDM, eat a strictly plant-based diet they face the risk of
developing nutrient deficiencies that may hinder their chances of sustaining a
healthy pregnancy and delivering a healthy baby.
What Is
Gestational Diabetes?
GDM is a carbohydrate intolerance that
begins or is first recognized during pregnancy. The condition is characterized
by hyperglycemia and associated with a host of complications to the fetus and
newborn, including macrosomia, birth trauma, hyperbilirubinemia, hypoglycemia,
respiratory distress syndrome, and childhood obesity. The children of women
with GDM also have higher rates of prediabetes and type 2 diabetes compared
with children of mothers who don’t have GDM.
Hyperglycemia during pregnancy also can
affect the mother, predisposing her to preeclampsia, Cesarean delivery, and an
increased risk of developing type 2 diabetes later in life.
The incidence of GDM is on the rise in the
United States, and it currently affects approximately 7% of all pregnancies. Fueled
by the ongoing obesity epidemic along with new diagnostic criteria, experts
anticipate the number to increase to 18%.3 As a result, dietitians can expect
to counsel more women with GDM.
According to the American Diabetes
Association (ADA), the ongoing obesity epidemic has led to more type 2 diabetes
diagnoses in general and an increase in the number of pregnant women with
undiagnosed type 2 diabetes. Because of this, the ADA recommends screening
women who have risk factors for the disease at their initial prenatal visit
using standard diagnostic criteria.
Based on the 2008 Hyperglycemia and
Adverse Pregnancy Outcome study, the ADA added diagnostic criteria for GDM to
the 2014 Standards of Diabetes in Medical Care. The new guidelines suggest that
all women not known to previously have diabetes undergo a 75-g oral glucose
tolerance test at 24 to 28 weeks gestation. Under the new guidelines, more
diagnoses of GDM are expected because only one abnormal value is sufficient to
make a diagnosis. Doctors make a GDM diagnosis if a patient exceeds any of
the following plasma glucose measures: Fasting: 92 mg/dL or greater; 1 hour:
180 mg/dL or greater; or 2 hours: 153 mg/dL or greater.
Dietitians’ Challenges
Since a plant-based diet doesn’t include
meat, fowl, or seafood, or products containing those foods, one challenge for
dietitians working with vegetarian GDM patients involves developing nutrition
plans that address the diverse types and eating patterns of a vegetarian.
The lacto-ovo vegetarian diet focuses on
grains, vegetables, fruits, legumes, seeds, nuts, dairy products, and eggs. The
lacto-vegetarian excludes eggs as well as meat, fish, and fowl. The vegan
diet—sometimes described as the total vegetarian—excludes eggs, dairy, and all
other animal products. But that’s not all: Some vegetarians eat fish and refer
to themselves as pescatarians; others consume a mostly plant-based diet and
call themselves flexitarians; and then there are 22.8 million Americans who say
they follow a vegetarian-inclined diet.
Research on the nutrient intake
of pregnant vegetarians is limited. However, studies show pregnant vegetarians
in general get less vitamin B12 and C, calcium, and zinc than their
nonvegetarian counterparts. The Dietary Reference Intake (DRI) for all pregnant
women aged 18 and older is 2.6 mcg of vitamin B12, 80 mg of vitamin C, 1,000 mg
of calcium, and 11 mg of zinc daily. If their dietary intake doesn’t meet the
DRI, dietitians should recommend a vitamin and mineral supplement to prevent
deficiencies.
Evidence-based analyses of available
studies also indicate that pregnant vegetarians eat less protein and higher
levels of carbohydrate than pregnant nonvegetarians. The Institute of Medicine
recommends 175 g of carbohydrate per day during pregnancy. During the last
trimester, pregnant women require additional carbohydrates to ensure adequate
glucose for the developing fetal brain. Eating a diet high in carbohydrates,
however, is especially problematic for pregnant GDM patients who need to
control blood glucose levels.
Medical Nutrition
Therapy
Medical nutrition therapy (MNT) with an
emphasis on controlling carbohydrate intake in GDM patients is considered
first-line therapy and often the only therapy that will normalize blood glucose
levels in women with GDM. Because vegetarian diets emphasize fruits,
vegetables, beans, and whole grains, they’re inherently high in carbohydrates.
Most vegetarians believe they can eat plenty of corn, peas, potatoes, and yams,
but these are starchy vegetables and must be eaten in moderation. In GDM meal
planning, these starches count as one carbohydrate and one protein serving,
providing 15 g of carbohydrate and 7 g of protein.
Gaining glycemic control quickly is
essential to preventing complications associated with GDM, so it’s important
for dietitians to carefully counsel mothers and develop meal plans that fit
their unique lifestyles. RDs also must consider that the first meal of the day
is physiologically the meal that GDM patients show the greatest insulin
resistance. As a result, dietitians will need to limit these patients’
carbohydrate intake to no more than 30 g at breakfast. In addition, they’ll
need to space carbohydrate intake throughout the day among three small- to
moderate-size meals and two to four snacks. The Academy suggests GDM patients
get 15 to 30 g of carbohydrate for breakfast, 45 to 60 g for lunch and dinner,
and 15 to 30 g for snacks.
To ensure GDM patients eat healthfully to
help control blood sugar and get the nutrients they need, leading health
authorities suggest they receive nutrition counseling from an RD at the time of
diagnosis.4 The Academy recommends MNT be initiated within one week of a GDM
diagnosis, with a minimum of three nutrition counseling visits. Research
studies show implementing this recommendation decreases hospital admissions and
insulin use, improves the likelihood of normal fetal and placental growth, and
reduces risk of perinatal complications.
Self-Monitoring of Blood Glucose
Dietitians also should advise pregnant
women with GDM to self-monitor fasting and postprandial blood glucose levels.
Several studies report a correlation between elevated fasting and postprandial
blood glucose values with poor maternal and neonatal outcomes.
RDs should review the self-monitoring of
blood glucose, record and use the results to evaluate the effectiveness of
nutrition intervention and lifestyle modifications, and the need for possible
pharmacological therapy. The ADA recommends GDM patients meet the following
glucose goals: preprandial: 95 mg/dL or lower; 1-hour postprandial: 140 mg/dL
or lower; and 2-hour postprandial: 120 mg/dL or lower.
Regular Exercise
Physical activity is another effective
means of controlling blood sugar. Unless contraindicated, dietitians should
recommend 30 minutes of physical activity for a minimum of three days per
week. Research indicates regular exercise during pregnancy reduces the common
discomforts of pregnancy without a negative effect on maternal or neonatal
outcomes and improves glycemic control in those with GDM.
Medication
If patients can’t control their blood
sugar with MNT and regular physical activity, their physician may need to
prescribe medications. Research indicates pharmacological therapy improves
glycemic control and reduces the incidence of poor maternal and fetal outcomes.
Traditionally, women who have been unable
to achieve and maintain normal blood glucose levels with MNT alone have been
prescribed insulin. However, recently doctors have been prescribing glyburide
and metformin to GDM patients, although the FDA hasn’t approved either of these
medications to treat gestational diabetes. Glyburide is the only antiglycemic
medication that’s been well studied in pregnant women. According to the
Academy’s Evidence Analysis Library, eight studies reported that glyburide was
effective in maintaining glycemic control with MNT.
Counseling Considerations
While advances in medicine have improved
the treatment of GDM, no one wants such a diagnosis. And although it may be for
only a matter of months, making lifestyle changes during pregnancy can be
stressful. Compounding the problem is the increase of hormones that work
against insulin and can cause blood glucose levels to rise.
Mothers may feel guilty and embarrassed if
they’re overweight and know their eating habits are less than ideal. Sarah
Krieger, MPH, RD, LD/N, an Academy spokesperson and a facilitator for the
Fit4AllMoms Study at All Children’s Hospital in St Petersburg, Florida,
accentuates the positive with her patients and tells them this is a perfect
time to begin a healthful lifestyle, increase physical activity, and avoid
gaining too much weight.
Others may be fearful of the prospect of
injecting insulin and may withhold or manipulate data in their self-monitoring
of blood glucose log or reduce food intake to control hyperglycemia. Some
women may become angry about having to change their lifestyle and begin paying
attention to food intake, carbohydrate counting, blood glucose monitoring, and
insulin injections, if required.
Dietitians should acknowledge that GDM can
be overwhelming. “I justify that first,” Krieger says. Emotional support and
education on GDM will ease women’s fears and can serve as a source of
motivation. “When they understand they don’t want a large baby or C-section,
moms are motivated to follow through by following recommendations,” she says.
Krieger advises dietitians to develop a
good working relationship with each patient’s doctor and understand what he or
she is telling the patient. “I work in a practice with six different doctors,
and they all don’t tell the patients the same thing,” she adds.
Optimistic Outlook
As mentioned, research supports that a
well-planned plant-based diet is appropriate during all stages of life,
including pregnancy. However, the inherently high carbohydrate content of a
vegetarian meal plan coupled with the emotional stress of GDM can be
challenging to both the mom-to-be and the dietitian. By educating patients
about GDM and walking them through the process of choosing nutritious foods and
taking the proper prenatal supplements to meet nutrient requirements, pregnant
women with GDM can expect to have a healthy pregnancy and baby.
All Fitness __ Plant-Based Diets and Gestational Diabetes
— Constance Brown-Riggs, MSEd, RD,
CDE, CDN, is the national spokesperson for the Academy of Nutrition and
Dietetics, specializing in African American Nutrition, and author of the African
American Guide to Living Well With Diabetes and Eating Soulfully
and Healthfully With Diabetes.
LACTO-VEGETARIAN MEAL PLAN
This exchange-based menu was developed
based on an intake of 180 g of carbohydrate, consisting of eight servings from
the starch group, two servings from the fruit group, and two servings of nonfat
dairy:
Breakfast: 1 slice whole wheat toast with 2 T of almond
butter (15 g carbohydrate)
Snack: 12 to 14 grapes with 1 oz cheese (15 g
carbohydrate)
Lunch: 1 cheese quesadilla or 1 sandwich with
baked tofu, mixed green salad with nuts, low-fat dressing, 1 cup nonfat yogurt
(45 g carbohydrate)
Snack: 1 small apple, roasted soy nuts, and 1 oz
of pretzels (30 g carbohydrate)
Dinner: 1⁄2 cup vegetarian chili, 1⁄2 tempeh wrap,
and vegetable wrap (45 g carbohydrate)
Snack: 8 oz nonfat milk and five whole wheat
crackers with 1 oz cheese (30 g carbohydrate)
— ADAPTED FROM VEGETARIAN NUTRITION
UPDATE,
RECOMMENDATIONS FOR GDM PATIENTS
The Academy of Nutrition and Dietetics
(the Academy) has developed the following nutrition intervention recommendations
for gestational diabetes mellitus (GDM) patients as part of its evidence-based
nutrition practice guidelines:
• Weight loss during pregnancy isn’t
recommended. Research indicates that low or inadequate weight gain during
pregnancy is associated with an increased risk of preterm delivery, regardless
of prepregnancy BMI levels. However, a modest energy restriction—approximately
70% of the Dietary Reference Intake (DRI) for pregnant women—will promote a slowing
of maternal weight gain. A minimum of 1,700 to 1,800 kcal/day should be
obtained to prevent maternal or fetal compromise or ketonuria.
Sarah Krieger, MPH RD, LD/N, a facilitator
of the Fit4AllMoms study in which one of three participants has GDM, notes that
study participants are provided 1,800 to 2,200 kcal/day based on BMI. “We look
at the whole picture, how much total weight gain there is and know that
appetite fluctuates,” Krieger says. “Most ladies do well with eating balanced
meals including protein, checking serum glucose, and walking daily.”
• Based on the DRI, a minimum of 175 g of
carbohydrate per day is encouraged to provide adequate glucose for fetal brain
development and prevent ketosis. Total carbohydrate intake should be less than
45% of total calories to prevent hyperglycemia. Elevated postprandial blood
glucose levels are associated with large-for-gestational-age infants and
increased rates of C-sections.
• Protein and fat should be calculated to
provide 10% to 35% and 20% to 35% of the DRI for energy, respectively. The
Recommended Dietary Allowance for pregnancy is 1.1 g/kg of protein per day, or
an additional 25 g of protein per day.
• If women with GDM choose to use products
containing nonnutritive sweeteners, dietitians should inform these women that
they should consume only FDA-approved nonnutritive sweeteners and suggest they
use them in moderation. Aspartame, acesulfame potassium, sucralose, saccharin,
and neotame are FDA approved for general use.
—
CBR
VEGAN MEAL PLAN
This menu was developed based on an intake
of 195 g of carbohydrate, including nine servings from the starch group, two
servings from the fruit group, and two servings of meat substitutes.
Breakfast: 1⁄4 cup of granola, 6 oz plain soy yogurt
(15 g carbohydrate)
Snack: 1⁄2 whole wheat pita bread with 2 T hummus
(30 g carbohydrate)
Lunch: 1 soy burger on a whole wheat bun, 8 oz
fortified flavored soy milk, green salad with low-fat dressing (45 g
carbohydrate)
Snack: 1 small fruit with 2 T peanut butter, 1
cup flavored soy yogurt (30 g carbohydrate)
Dinner: 1 cup quinoa, stir-fried tofu with mixed
vegetables (45 g carbohydrate)
Snack: Five whole wheat crackers with tahini, 1
fruit (30 g carbohydrate)
— ADAPTED FROM VEGETARIAN NUTRITION
UPDATE
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