Japanese health experts have updated their nutrition guidelines for pregnant and nursing mothers, focusing on how what moms eat affects their babies’ health—both before birth and throughout life. The new 2025 guidelines recommend specific amounts of energy and nutrients for each trimester of pregnancy. However, research shows many Japanese women aren’t getting enough of important nutrients like folate and vitamin D. The guidelines also highlight concerns about anemia in pregnant women and the need for better nutrition advice for women planning to get pregnant and those breastfeeding. While the new guidelines provide a helpful framework, doctors and researchers say more work is needed to help women actually follow these recommendations.
The Quick Take
- What they studied: What nutrients pregnant and nursing mothers in Japan should eat, and whether current guidelines match what women actually consume and what science shows is healthy
- Who participated: This was a review of existing guidelines and Japanese research studies—not a study of individual people, but rather an analysis of nutrition recommendations and data from multiple studies
- Key finding: Japan’s new nutrition guidelines provide trimester-by-trimester targets, but many Japanese women aren’t eating enough nutrients, especially folate and vitamin D, which are crucial for baby development
- What it means for you: If you’re pregnant or planning to become pregnant, these guidelines can help you understand what nutrients matter most. However, you should work with your doctor to make sure you’re getting enough, especially if you’re at risk for anemia or vitamin D deficiency
The Research Details
This is a narrative review, which means experts gathered and summarized information from Japan’s official nutrition guidelines and recent Japanese research studies about pregnant and nursing mothers. Rather than conducting a new experiment, the authors looked at what the guidelines recommend and compared those recommendations to what actual research shows about Japanese women’s eating habits and health outcomes. They examined studies on topics like how much weight women should gain during pregnancy, folate intake, vitamin D levels, calcium needs, and how nutrition affects baby growth and maternal health. This type of review helps identify gaps between what guidelines say and what’s actually happening in real life.
Understanding what pregnant women actually eat versus what they should eat is important because it shows where education and support are needed. By reviewing both guidelines and real-world data, experts can identify which nutrients are most commonly lacking and which health problems (like anemia) are most common. This helps doctors and public health officials know where to focus their efforts to improve outcomes for mothers and babies.
This is an expert commentary and review rather than a research study testing new ideas. The authors are summarizing official guidelines and existing research, which makes it reliable for understanding current recommendations. However, because it’s not a new experiment with participants, it doesn’t provide new evidence—it organizes and explains existing knowledge. The strength comes from the authors’ expertise and their careful review of both guidelines and Japanese research studies.
What the Results Show
Japan’s 2025 Dietary Reference Intakes provide specific nutrition targets that increase by trimester (first, second, and third three-month periods of pregnancy). The guidelines recommend additional calories and nutrients as pregnancy progresses, which makes sense because the baby grows more in later months. However, when researchers looked at what Japanese women actually eat, they found many women aren’t getting enough total calories, protein, vitamins, and minerals. This gap between recommendations and reality is a major concern. Folate (a B vitamin crucial for baby’s brain and spine development) is particularly low in many Japanese women’s diets, and awareness about why folate matters is limited. Vitamin D and calcium, which are essential for both mother’s and baby’s bone health, are also commonly insufficient in Japanese women’s diets.
The review identified several other important nutrition issues: Anemia (low iron in the blood) affects some pregnant Japanese women and is linked to problems like premature birth and low birth weight. The guidelines mention that women with gestational diabetes (high blood sugar during pregnancy) need special nutrition care, but specific nutrient targets haven’t been set yet. For women with high blood pressure during pregnancy, the guidelines recommend eating less salt but don’t provide complete nutrition guidance. The review also notes that there’s limited guidance for women who are planning to become pregnant and for women who are breastfeeding, even though nutrition matters during these periods too.
This 2025 update builds on previous Japanese nutrition guidelines and incorporates newer understanding about how a mother’s nutrition affects her baby’s lifelong health—a concept called ‘Developmental Origins of Health and Disease.’ The new guidelines are more detailed about trimester-specific needs than older versions. However, the core challenge remains the same: knowing what women should eat is only part of the solution; the bigger problem is helping women actually achieve these nutrition goals in their daily lives.
This is a review of guidelines and existing studies, not a new research study, so it doesn’t provide new evidence about what works best. The review focuses on Japanese women and Japanese research, so findings may not apply to other populations. The authors note significant gaps in research—for example, there’s limited data on how much weight different women should gain based on their starting body size, and there’s not enough research on how specific nutrients affect fetal growth. The review also highlights that we need better ways to help women actually follow nutrition recommendations, not just know what they should do.
The Bottom Line
If you’re pregnant or planning to become pregnant: (1) Eat enough calories and protein—your needs increase as pregnancy progresses; (2) Make sure you’re getting folate from foods like leafy greens, beans, and fortified grains, or take a folate supplement as recommended by your doctor; (3) Get adequate vitamin D and calcium for bone health; (4) Have your blood checked for anemia and work with your doctor if you have it; (5) If you have gestational diabetes or high blood pressure, work with a nutrition specialist. These recommendations have moderate to strong evidence support, but individual needs vary.
These findings are most relevant to pregnant women in Japan and healthcare providers caring for them. Women planning to become pregnant should also pay attention to these nutrition principles. The findings may also be relevant to pregnant women in other Asian countries with similar diets. If you have specific health conditions like anemia, gestational diabetes, or high blood pressure during pregnancy, nutrition becomes even more important. However, these are general guidelines—your individual needs may differ based on your health status, so discuss with your doctor.
Good nutrition during pregnancy affects your baby immediately and throughout their life. You may notice improved energy and fewer pregnancy complications within weeks of improving your nutrition. Your baby’s development happens continuously throughout pregnancy, so starting good nutrition habits as early as possible—ideally before pregnancy—is ideal. The long-term benefits for your child’s health may not be obvious for years or decades.
Want to Apply This Research?
- Track daily intake of key nutrients: folate (micrograms), vitamin D (IU), calcium (mg), iron (mg), and total calories. Set trimester-specific targets based on guidelines and log meals to see if you’re meeting them. Weekly summaries help identify which nutrients need attention.
- Create a simple meal plan that includes one folate-rich food daily (spinach, lentils, asparagus), one calcium source (dairy or fortified alternatives), and track vitamin D intake. Use the app to set reminders for prenatal vitamin supplements and log any symptoms like fatigue that might indicate anemia.
- Monthly check-ins comparing your nutrient intake to trimester-specific targets. If gaps appear (especially in folate, vitamin D, or calcium), adjust meals or supplements. Share monthly summaries with your healthcare provider to ensure you’re on track and discuss any concerns about anemia or other pregnancy-related nutrition issues.
This summary is for educational purposes and should not replace professional medical advice. Nutrition needs during pregnancy are individual and depend on your health status, body composition, and any pregnancy complications. Always consult with your obstetrician, midwife, or registered dietitian before making significant changes to your diet or starting supplements during pregnancy. If you have anemia, gestational diabetes, high blood pressure, or other pregnancy-related conditions, nutrition management should be supervised by your healthcare team. This information is based on Japanese guidelines and may not apply to all populations.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.