Best Nuts During Pregnancy: Safety and Benefits | Nut Cravings
Most pregnancy nutrition guides tell you walnuts have omega-3 and almonds have folate and leave it there. The actual research goes much further. A 2025 cohort study tracked 1,737 mother-child pairs to age 15 and found higher maternal nut intake in pregnancy was associated with better child attention, working memory, and fluid intelligence, with omega-3 from nuts mediating part of that effect. An earlier study on 2,208 pairs found the same pattern, with the strongest association in the first trimester. Here's what the evidence actually says, nut by nut.
Nuts are safe and beneficial throughout pregnancy. Walnuts are the top choice for fetal brain development (ALA omega-3, confirmed in two INMA cohort studies to support child cognition). Almonds provide dietary folate, magnesium (protecting against gestational diabetes and preeclampsia), and vitamin E. Brazil nuts cover selenium needs for thyroid function at just 1 to 2 per day. Cashews contribute iron and magnesium. One ounce of mixed tree nuts daily is safe for all three trimesters. Eating nuts during pregnancy does NOT cause baby nut allergies (NHS guidance 2023 reversed the old advice). Choose unsalted, raw or dry-roasted. Limit Brazil nuts to 1 to 2 daily.
What Two Large Cohort Studies Say About Nuts and Child Brain Development
The conversation about nuts and pregnancy has been dominated by generic nutrient lists for years. The research that should be driving it is considerably more specific and more recent.
This study followed 1,737 mother-child pairs from four Spanish regions, evaluating maternal diet during pregnancy and children's neuropsychological function through standardized computer-based tests at multiple ages up to 15 years. Outcomes measured included attention (hit reaction time and variability via the Conners' Kiddie Continuous Performance Test and Attention Network Test), working memory (N-back task detectability), and fluid intelligence (Raven's Progressive Matrices and Primary Mental Abilities test).
Higher maternal nut consumption during pregnancy was associated with improved neuropsychological function across these measures. Critically, the researchers modeled the potential mediating role of omega-3 fatty acids and found that omega-3 from nuts mediated part of this association. The study concluded that maternal diet at pregnancy, particularly omega-3 intake from nuts and seafood, may support long-term cognitive development in children and adolescents.
This earlier study used the Bayley Scales of Infant Development (18 months), McCarthy Scales of Children's Abilities (5 years), and the Attention Network Test and N-Back test (8 years). Children whose mothers consumed the most nuts in the first trimester of pregnancy scored best on all tests measuring cognitive function, attention, and working memory at all three assessment points. The association was stronger for first-trimester nut consumption than third-trimester, suggesting the timing of nut intake within pregnancy may matter, not just the overall amount.
The first trimester covers weeks 5 through 13. Neural tube formation begins as early as week 5. Rapid neuron multiplication follows in the second trimester at up to 250,000 neurons per minute. The nutrients that support neural architecture, particularly DHA and its precursors along with folate and magnesium, are most critical during active neural formation phases. The first-trimester finding is consistent with this developmental biology.
Important context: Both INMA studies are observational cohort studies, not randomized controlled trials. Women who eat more nuts during pregnancy may differ in many other health behaviors. Researchers adjusted for known confounders, but residual confounding is always possible in this study design. These findings don't prove that eating nuts causes better cognitive outcomes. They support the biological plausibility and motivate further research, including the planned WALNUT RCT assessing daily walnut consumption on adolescent cognition. Treat this as strong supportive evidence alongside the established nutrient mechanisms, not as proof of a definitive causal relationship.
Why Walnuts Are the Most Important Nut for Fetal Brain Development
The brain doesn't grow evenly throughout pregnancy. The first trimester is when the neural tube forms and the basic brain architecture is laid down. The third trimester is when the brain triples in weight. DHA comprises over 40 percent of polyunsaturated fatty acids in brain tissue and is the primary structural fat in neural cell membranes. It's transferred from the mother to the fetus throughout pregnancy, with transfer accelerating dramatically in the third trimester.
Walnuts are the richest whole-food plant source of ALA (alpha-linolenic acid), the plant-based omega-3. One ounce of raw walnuts provides 2.5 grams of ALA. The body converts ALA to EPA and then to DHA, though the conversion rate is limited, roughly 5 to 10 percent of ALA to EPA and less than 1 percent to DHA directly. This means walnuts are a meaningful contributor to the omega-3 pathway but don't replace oily fish or a DHA supplement as the primary DHA source in a pregnancy diet. They work alongside those sources, not instead of them.
For vegetarian and vegan pregnant women who aren't eating oily fish, walnuts become even more important as the primary dietary ALA source, paired with an algae-based DHA supplement to directly address the conversion limitation.
The mechanism: how ALA from walnuts reaches the developing brain
Omega-3 fatty acids get incorporated into the phospholipid bilayers of cell membranes throughout the body, including in neural cells. DHA specifically accumulates in the grey matter of the brain and in photoreceptors of the retina. During rapid fetal brain growth, adequate DHA availability supports synaptogenesis (the formation of connections between neurons), myelination (insulation of neural pathways that speeds signal transmission), and microglial function (the brain's immune cells, which play a role in synaptic pruning during development).
The 2025 INMA study found that omega-3 from nuts mediated the association between maternal nut intake and child attention outcomes, confirming the proposed ALA pathway is operating at a population level. The finding held from ages 4 to 15, suggesting the effects on neural architecture from prenatal exposure have persistence across development.
Almonds During Pregnancy: Folate, Magnesium, and Vitamin E
Almonds carry three nutrients that matter specifically during pregnancy: dietary folate, magnesium, and vitamin E.
Folate and neural tube protection
Folate is the natural dietary form of the B vitamin that the US Public Health Service and Mayo Clinic identify as the most critical nutrient during early pregnancy. The recommended intake is 600 micrograms daily throughout pregnancy, with the neural tube formation window in weeks 5 to 7 being particularly sensitive. Almonds provide dietary folate (not the synthetic folic acid in supplements, but naturally occurring folate from food), contributing to the mixed dietary plus supplemental approach that nutritional guidelines recommend.
One ounce of raw almonds provides about 14 micrograms of folate, which is a meaningful contribution when you're eating almonds as a consistent daily snack alongside other folate-rich foods like leafy greens and legumes. The Mayo Clinic's guidance is explicit: folate intake should begin before conception and continue throughout pregnancy, making daily almond consumption a reasonable dietary habit to establish before trying to conceive.
Magnesium and gestational diabetes risk
This connection is substantially underreported in pregnancy nutrition content. A 2024 review published in Food Science and Nutrition confirmed that magnesium deficiency during pregnancy is linked to gestational diabetes, preeclampsia, preterm birth, and low birth weight. Pregnancy itself increases magnesium requirements, and research consistently shows pregnant women in many countries have inadequate magnesium intake.
Magnesium is required for glucose metabolism and insulin sensitivity. During pregnancy, insulin resistance naturally increases, particularly in the third trimester, and adequate magnesium supports the metabolic mechanisms that keep blood glucose controlled. One ounce of raw almonds provides 77 milligrams of magnesium, covering 18 percent of the daily value. One ounce of raw cashews provides 74 milligrams. Eating both as part of a daily diet provides over a third of the DV toward the higher requirement that pregnancy creates.
Vitamin E and placental health
Almonds are the richest common food source of vitamin E, providing 7.3 milligrams per ounce (49 percent of the daily value). During pregnancy, vitamin E's antioxidant function helps protect cell membranes from oxidative stress, which is particularly relevant for placental tissue and for the developing fetus's own cells. Research on vitamin E and pregnancy outcomes is less conclusive than for folate or DHA, but the contribution to an overall antioxidant-rich diet is well-supported as beneficial.
Why Magnesium Deficiency in Pregnancy Is More Consequential Than Most Guides Acknowledge
Gestational diabetes affects approximately 14 percent of pregnancies globally and is among the most significant preventable adverse pregnancy outcomes. The connection between magnesium intake and gestational diabetes risk operates through insulin signaling: magnesium is a cofactor in over 300 enzymatic reactions, including multiple steps in glucose metabolism and insulin receptor signaling.
A 2024 Food Science and Nutrition systematic review synthesized the evidence: "Magnesium deficiency can lead to complications, such as gestational diabetes, preeclampsia, preterm birth, and developmental abnormalities." Preeclampsia, characterized by high blood pressure and organ damage, is serious for both mother and fetus. While the causal direction in observational data isn't always clear, the biological mechanisms for magnesium's protective role are well-documented at the cellular level.
For practical purposes: a pregnant woman eating an ounce of almonds and an ounce of cashews daily gets about 151 milligrams of magnesium from those two snacks alone, roughly 40 percent of the 400 milligram daily target for pregnant women. Combined with magnesium from other foods (spinach, legumes, whole grains), meeting requirements through diet becomes achievable without supplementation for most women with a varied diet.
First-trimester practical note: If you're experiencing nausea in the first trimester, small servings of mild-tasting nuts like cashews or macadamias are often easier to tolerate than stronger-flavored options. The INMA data suggests the first trimester is the most important window for nut consumption and cognitive outcomes in children. Finding formats that work even during nausea (nut butter on crackers, cashews in small amounts with other foods) is worth the effort.
Brazil Nuts and Selenium: The Pregnancy Nutrient Most Articles Skip
Selenium's role in pregnancy is almost completely absent from mainstream pregnancy nutrition content. It shouldn't be. Selenium is required for thyroid hormone synthesis and regulation, and maternal thyroid function is critical throughout pregnancy for both the mother's health and fetal neurological development. The fetus depends entirely on maternal thyroid hormone until its own thyroid becomes functional around week 12.
Selenium deficiency in pregnancy increases the risk of postpartum thyroiditis, adverse pregnancy outcomes, and may affect fetal neurological development through thyroid hormone insufficiency. Just 1 to 2 Brazil nuts daily provides the full recommended daily selenium intake of 55 to 70 micrograms (raised to 60 mcg during pregnancy). This is also the only part of the guide where a hard ceiling exists: don't eat a large bag of Brazil nuts regularly. The upper tolerable limit is 400 micrograms daily, and eating more than 2 to 3 Brazil nuts every day could approach or exceed this over time.
For more on the precise selenium dosing research and what the science says about safe upper limits, see the detailed Brazil nuts per day guide.
The Complete Pregnancy Nut Guide: What Each Nut Provides
| Nut | Key pregnancy nutrients | Why it matters | Safe daily amount |
|---|---|---|---|
| Walnuts | 2.5g ALA omega-3, 4g protein, folate, magnesium, polyphenols | Two INMA cohort studies link maternal walnut intake to better child cognition to age 15. ALA mediates part of the effect. | 1 oz (28g). Eat raw to preserve ALA. Store in fridge. |
| Almonds | 14mcg folate, 77mg Mg (18% DV), 7.3mg vitamin E (49% DV), 6g protein | Dietary folate for neural tube. Magnesium protects against gestational diabetes and preeclampsia. Highest vitamin E of any nut. | 1 oz (28g) daily. Unsalted raw preferred. |
| Brazil nuts | Selenium 68-91mcg per nut, magnesium | Selenium for maternal thyroid function and fetal neurological development. Thyroid hormones regulate fetal brain development until week 12. | 1 to 2 nuts only. Do not exceed daily. |
| Cashews | 74mg Mg (18% DV), 5g protein, iron, zinc, L-arginine | Magnesium for gestational diabetes risk. Iron supports increased maternal blood volume and prevents anemia. Tolerated well during nausea. | 1 oz daily. Unsalted. Often easier during first-trimester nausea. |
| Pistachios | 6g protein (DIAAS 86), folate, potassium, antioxidants | Highest quality plant protein of any tree nut. Potassium supports healthy blood pressure, particularly relevant given preeclampsia risk. | 1 oz daily. Unsalted. In-shell slows eating pace. |
| Hazelnuts | Folate, vitamin E, copper, manganese | Folate contribution. Copper is important for fetal cardiovascular development. High MUFA content for sustained energy. | 1 oz daily. Often tolerated well in nausea. |
| Pecans | Zinc, magnesium, manganese, polyphenols | Zinc supports immune function and protein synthesis during rapid fetal growth. Low carb option for women managing gestational diabetes. | 1 oz daily. Good option for GDM-managed diets. |
Does Eating Nuts During Pregnancy Cause Nut Allergies in Babies?
This question persists because the old advice said to avoid nuts during pregnancy. That advice was wrong and has been formally reversed.
The outdated guidance came from the 1990s hypothesis that early exposure to allergenic foods through the maternal diet might sensitize the fetal immune system. This was precautionary, not evidence-based, and subsequent research found no support for it. The NHS updated its official guidance in 2023 to explicitly state: "Eating nuts when pregnant will not affect whether or not your baby has a peanut allergy."
The current scientific understanding of food allergy development actually points in the opposite direction. The immune system's development during the fetal period may benefit from maternal dietary exposure to common food proteins, potentially reducing the likelihood of later allergy through immune tolerance mechanisms. The evidence for this hypothesis in humans is not conclusive enough to make it a positive recommendation, but it removes any basis for the old avoidance advice.
The only legitimate reason to avoid nuts during pregnancy is a personal nut allergy. If you're allergic, don't eat them. If you're not, there's no current evidence that eating nuts increases your child's allergy risk, and good evidence that they provide meaningful nutritional benefits for both you and the developing fetus.
What Makes Nut Cravings Different for Pregnant Women
The research that links maternal nut intake to child cognitive outcomes used dietary nuts, not supplements. The ALA omega-3 in walnuts that mediates the effect on fetal brain development degrades with oxidation. Walnuts that have been sitting in a grocery store warehouse for months have already lost a portion of their ALA content to rancidity before you open the bag. The polyphenols in almonds that contribute to their antioxidant effects are similarly affected by time and storage conditions.
At Nut Cravings, we pack from current-season California stock at our Monroe, NY facility and ship directly to you. Your walnuts arrive at the start of their oxidation clock. The resealable bags close properly after each serving, protecting the delicate ALA fats in walnuts and the vitamin E in almonds between uses. For a pregnant woman eating nuts daily throughout pregnancy, starting with fresh stock and keeping it fresh between servings is how the nutritional value in the research translates to the nutritional value in your actual diet.
Everything is unsalted. Sodium intake needs are already managed carefully during pregnancy, and there's no reason to add unnecessary salt to any of our nuts. OU Kosher certification covers the full catalog through third-party facility inspection and auditing. Featured on Good Morning America.
"I'm in my second trimester and specifically wanted raw walnuts and unsalted almonds for the pregnancy benefits. Both arrived incredibly fresh, which made me feel better about actually getting the nutrition I was paying for. The bag closures are properly functional which sounds minor but matters a lot when you're snacking daily."
"My OB told me to eat more nuts for the omega-3 and magnesium during pregnancy. I started with the mixed bag and the walnuts separately. The freshness difference from what I was buying at the grocery store is completely noticeable. My husband even commented on it before I mentioned the brand."
Your Nuts and Pregnancy Questions Answered
Yes. All tree nuts are safe to eat during pregnancy unless you have a personal nut allergy. The NHS updated its guidance in 2023 to explicitly confirm that eating nuts during pregnancy does not increase your baby's risk of developing a nut allergy. Nuts are recommended as part of a varied, nutritious pregnancy diet for their folate, omega-3, magnesium, protein, and vitamin E content. Choose unsalted raw or dry-roasted varieties. The one exception within the nut category is Brazil nuts: limit to 1 to 2 per day because of their very high selenium content, which becomes problematic in large daily amounts.
Walnuts are the top choice for fetal brain development as the richest plant source of ALA omega-3. Two INMA cohort studies following thousands of mother-child pairs found higher maternal nut consumption in pregnancy was associated with better child attention, working memory, and fluid intelligence, with omega-3 mediating part of this effect. Almonds are valuable for dietary folate, magnesium, and vitamin E. Brazil nuts cover selenium in just 1 to 2 nuts daily. Cashews contribute magnesium and iron and are often tolerated well during first-trimester nausea. Mixed nuts provide the broadest nutritional coverage across all these nutrients in a single daily snack.
One ounce (28 grams, a small handful) of tree nuts daily is safe and nutritionally beneficial throughout all three trimesters. This is the serving size used in most research and consistent with dietary guidelines. For Brazil nuts specifically, the limit is 1 to 2 nuts per day because of their exceptionally high selenium content. For all other tree nuts, a one-ounce serving daily is appropriate. You can vary the nut type by day or eat mixed nuts to cover the full spectrum of nutrients in a single serving.
No. This was outdated precautionary advice that has been reversed. The NHS 2023 guidance explicitly states that eating nuts during pregnancy will not affect whether your baby develops a nut allergy. Multiple studies found no link between maternal nut consumption and increased nut allergy risk in children. Current research does not support the old avoidance recommendation. You should avoid nuts only if you personally have a diagnosed nut allergy. If you're not allergic, there's no evidence-based reason to restrict nuts during pregnancy.
The evidence strongly supports a link, though most studies are observational. Walnuts are the richest whole-food plant source of ALA omega-3 at 2.5 grams per ounce. ALA converts to DHA, which is the primary structural fat in neural cell membranes and is essential for brain development. A 2025 cohort study in the American Journal of Clinical Nutrition following 1,737 mother-child pairs to age 15 found omega-3 from nuts mediated improved attention, working memory, and fluid intelligence in children. An earlier 2019 INMA study on 2,208 pairs found the same pattern with the strongest association in the first trimester. These are observational cohort studies, not randomized trials, so they support but don't prove causation. DHA from oily fish or algae supplements is more bioavailable than ALA from walnuts, so walnuts complement rather than replace other DHA sources in a pregnancy diet.
Recommended Pregnancy Nuts
California-grown. No added salt or oil. Packed from current-season stock for maximum nutritional freshness.
"Second trimester and specifically wanted raw walnuts and unsalted almonds for the pregnancy benefits. Both arrived incredibly fresh. Bag closures work properly, which matters when you're snacking daily throughout pregnancy."
"My OB told me to eat more nuts for omega-3 and magnesium during pregnancy. The freshness difference from grocery store nuts is completely noticeable. My husband commented on it before I even mentioned the brand."
"Pregnant with my second and I've been buying nuts here through both pregnancies. The Brazil nuts in particular are noticeably fresher than what I could find locally. I eat one or two a day for the selenium and get the walnuts for the omega-3. The quality justifies the direct order every time."
2.5g ALA omega-3/oz. Top choice for fetal brain development. INMA cohorts 2019 and 2025.
Folate + 18% Mg/oz. Gestational diabetes and preeclampsia protection. 49% DV vitamin E.
Selenium for thyroid function. 1-2 per day covers full daily requirement. Limit strictly.
18% Mg/oz, iron, zinc. Mild taste tolerated during first-trimester nausea. No added salt.
DIAAS 86 protein quality. Potassium for blood pressure. Folate. Antioxidant polyphenols.
ALA, folate, Mg, selenium, protein all in one snack. Broadest coverage for pregnancy nutrition.
Why Choose Nut Cravings During Pregnancy
The research on nuts and pregnancy outcomes used dietary nuts. The ALA omega-3 that mediates the INMA cognitive outcomes degrades with oxidation. The magnesium in almonds is stable, but the vitamin E and polyphenols are not. Starting with fresh nuts is how the nutrition in the studies translates to the nutrition in your actual diet.
Packed fresh from current California harvests
Walnuts' ALA omega-3 content degrades when the fat oxidizes. Almonds' vitamin E and polyphenols degrade over time. We pack at our Monroe, NY facility from current California season stock without routing through regional distributors. Your nuts arrive at the start of their nutritional life, not months into it from a warehouse supply chain.
Unsalted across the full catalog
Sodium intake requires careful management during pregnancy, particularly given preeclampsia risk. All Nut Cravings nuts are available unsalted with no added ingredients. You're getting the nut and nothing else, which is what the research used and what pregnancy nutrition guidelines recommend.
OU Kosher certified across the full catalog
Third-party facility inspection and ongoing auditing from a recognized certifying body. An independent quality verification that can't be self-issued and requires real accountability to maintain. For anyone being careful about food quality during pregnancy, this provides verifiable assurance beyond a company's own quality claims.
Resealable bags that actually close properly
Walnut ALA oxidizes days after opening a bag left exposed to air. A bag that doesn't reseal properly means your pregnancy walnuts are losing their omega-3 value every day you're not eating from them. Our zipper-seal bags create a genuine oxygen barrier between servings. For a daily snack habit built on consistent ALA intake over nine months, this matters every time you open the bag.
All pregnancy-relevant nuts in one place
Walnuts for ALA omega-3. Almonds for folate, magnesium, and vitamin E. Brazil nuts for selenium at 1 to 2 per day. Cashews for iron and magnesium, tolerated during nausea. Pistachios for protein quality and potassium. The per-nut pregnancy table in this guide maps directly to what we stock, fresh and unsalted.
Featured on Good Morning America
Independent editorial recognition alongside OU Kosher certification and direct-from-packer freshness. Three verifiable external quality signals before your first order, for expectant parents who want evidence before they trust a brand with their pregnancy nutrition.