Nutrient Deficiencies Every Woman of Reproductive Age Should Know About — and How to Fix Them
I talk to women every day who are eating well, exercising, and doing all the “right” things, but they still feel tired, moody, or like their health just isn’t where they want it to be. Often, the missing piece isn’t more willpower or effort — it’s nutrients.
Deficiencies in key vitamins and minerals can quietly throw off your mood, energy, digestion, and even your chances of conceiving.
In this post, I’m breaking down the most common nutrient deficiencies in women, why they matter for fertility and hormone health, and exactly what you can do about them — from testing to practical lifestyle tips you can start today.
Why Nutrient Deficiencies Matter for Women’s Health (and fertility, too!)
Vitamins and minerals, aren’t just “nice to have”; they’re essential and they play a critical role in hormone production, thyroid function, energy levels and mood. Missing key nutrients can quietly affect your body in ways you might not even notice at first and even mild deficiencies can lead to subtle but impactful health issues, including:
Fatigue, low energy, or poor exercise recovery
Mood swings or brain fog
Irregular cycles or hormone imbalances
Digestive issues or poor nutrient absorption
And yes, even challenges with fertility or a higher risk of pregnancy complications
The good news? Being proactive about testing for and addressing deficiencies sets you up for better overall health today and lays the foundation for long-term wellness.
Common Nutrient Deficiencies in Women of Reproductive Age
Many women assume they’re getting all of the nutrients they need from their diet alone, but this isn’t always the case and unfortunately even small gaps in your needs can quietly impact your health. Here are the most common nutrients that tend to be low in women (and what signs to look out for):
Iron
Iron is an essential nutrient for energy production, brain function, and overall wellness. It’s a key part of hemoglobin, the protein in your red blood cells that carries oxygen to every part of your body. Without enough iron, your cells just don’t get the oxygen they need, which can leave you feeling tired and foggy (AKA, like complete cr*p), even if you’re eating well and sleeping enough.
Women are at higher risk for deficiency because of blood loss during their period, vegan or vegetarian diets, or increased needs during times of stress or growth.
Over time, deficiency can lead to anemia, making everyday tasks feel SO much harder than they should (kind of like you’re walking through quicksand).
Signs you might be low in Iron:
Feeling unusually tired or weak, despite enough sleep
Brain fog or difficulty concentrating
Feeling dizzy or lightheaded
Heavy or prolonged periods
Testing:
Ferritin, serum iron, and a complete blood count (CBC) are the most reliable ways to check your iron status.
Treatment & Support:
Add iron-rich foods to your diet, like lean red meat, lentils, spinach, pumpkin seeds and chickpeas
Pair plant-based iron sources of ironwith vitamin C (like citrus or bell peppers) to improve absorption
If your levels are low, supplementation may be needed. Your healthcare provider can guide you on the right form and dose
Vitamin D
Vitamin D is often called the “sunshine vitamin,” because your body naturally produces it when your skin is exposed to sunlight. It’s crucial for your immune system, mood, energy levels, bone health and even reproductive hormones.
Many women don’t get enough, especially if they live in northern climates, spend a lot of time indoors, or use sunscreen regularly (which is important, but it also limits vitamin D production).
Signs you might be low in vitamin D:
Feeling unusually tired or sluggish
Low mood or seasonal blues
Muscle aches or weakness
Frequent illnesses
Testing:
A simple blood test called 25-hydroxy vitamin D can show whether your levels are in the optimal range.
Treatment & Support:
Get safe sun exposure when possible.
Eat vitamin D-rich foods like fatty fish (salmon, sardines), fortified dairy or plant-based milks, and eggs
If your levels are low, a high-quality vitamin D3 supplement is the most effective way to restore them
Vitamin B12
B12 is a vitamin that’s necessary for red blood cell formation, nerve health, and DNA synthesis. Women following a plant-based or vegetarian diet are especially at risk for deficiency, but anyone can become deficient over time.
Signs you might be low in vitamin B12:
Feeling fatigued or weak
Brain fog or trouble concentrating
Tingling or numbness in your hands or feet
Pale skin or a general sense of low vitality
Elevated homocysteine (which can affect fertility)
Testing:
Serum B12 is a standard test, but methylmalonic acid (MMA) can be used to detect deficiency earlier, even before symptoms appear
Treatment & Support:
Include B12-rich foods like eggs, dairy, lean meats, and fortified plant-based options
For those who don’t get enough from diet, a methylcobalamin supplement is usually the most effective way to restore levels
Magnesium
Magnesium is a nutrient that your body quietly relies on for muscle function, stress management, sleep, and hormone balance. Low magnesium is surprisingly common and can show up as subtle symptoms that you might not even connect to a deficiency, like cramps, tension, or trouble winding down at night.
Signs you might be low in vitamin B12:
Muscle cramps or spasms
Trouble sleeping or staying relaxed
Increased stress or irritability
Digestive issues like constipation
Testing:
Magnesium levels can be checked with a serum magnesium test, though sometimes red blood cell (RBC) magnesium is used to provide a more accurate picture
Treatment & Support:
Eat magnesium-rich foods like leafy greens, nuts, seeds, whole grains, and dark chocolate
For extra support, consider a magnesium supplement, either oral or transdermal (like magnesium oil or bath flakes)
Folate (Vitamin B9)
Folate is essential for cell growth and DNA production. While most people hear about folate in the context of pregnancy, it’s just as important for general women’s health, supporting energy, brain function, and hormone balance. Low folate can leave you feeling tired or run down and may affect long-term wellness if not addressed.
Signs you might be low in folate:
Fatigue or low energy
Trouble concentrating or “brain fog”
Pale skin or general weakness
Testing:
Red blood cell (RBC) folate or serum folate can reveal whether your levels are sufficient
Testing is especially useful if you follow a vegetarian or vegan diet, or have genetic variations like MTHFR that affect folate metabolism
Treatment & Support:
Eat folate-rich foods like leafy greens, legumes, asparagus, avocados, and fortified grains
If needed, take a methylated folate supplement, which is easier for your body to use, particularly if you have an MTHFR gene variant
Omega-3 Fatty Acids
Omega-3s are essential fats your body can’t produce on its own, yet they’re crucial for heart health, brain function, hormone balance, and overall inflammation control. Many women don’t get enough, especially if they don’t regularly eat fatty fish or other omega-3-rich foods.
Signs you might be low in omega-3s:
Dry skin or hair
Brain fog or trouble focusing
Low mood or irritability
Joint stiffness or inflammation
Testing:
The Omega-3 Index is a blood test that measures your levels
Treatment & Support:
Eat fatty fish (like salmon, sardines, and mackerel) 2–3 times per week, if possible
For plant-based sources, include chia seeds, flaxseeds, hemp seeds, and walnuts
Supplements such as fish oil or algae-based omega-3s can help fill gaps if your diet is low
Testing and Treatment: A Functional Medicine Approach
The Importance of Individualized Testing
Knowing which nutrients you may be low in is the first step toward feeling your best. The tricky part is that symptoms can be subtle or overlap, which is why testing is so helpful — it takes the guesswork out of the equation and ensures you’re supporting your body the right way.
Step 1: Get tested
Work with a healthcare provider who understands women’s health and nutrition.
Common tests include CBC, ferritin, serum iron, vitamin D, vitamin B12, RBC folate, magnesium, and Omega-3 Index.
Regular testing can catch deficiencies early, before they even begin to impact energy, mood, or long-term health.
Step 2: Targeted support
Once you know your nutrient status, you can take strategic steps to restore any nutrient gaps:
Food first: Incorporate nutrient-rich whole foods daily.
Supplements when needed: If testing shows a deficiency, your provider can recommend the right form, dose, and timing. Not all supplements are created equal, so personalized guidance is key.
Lifestyle support: Factors like stress, sleep, and gut health affect nutrient absorption. Optimizing these areas ensures the nutrients you get actually reach your cells.
Step 3: Monitor progress
Recheck nutrient levels as recommended to ensure supplementation and dietary changes are working.
Adjust your plan as your body, cycle, or life circumstances change (what works at 25 may need tweaking at 30 or 35!).
The takeaway? You don’t have to guess or hope you’re getting enough nutrients. Testing, food, supplements, and lifestyle support give you a clear roadmap to feeling energized, balanced, and healthy, both now and for the long term.
Taking Charge of your Nutrient Health
It’s easy to assume that eating “well” is enough (I’d be lying if I said I haven’t fallen into that trap myself), but even the smallest nutrient gaps can quietly affect your energy, mood, hormones, and overall well-being. The good news? Once you know your nutrient status, you can take practical, targeted steps to support your body and the results can be truly transformative.
Start with testing, focus on whole-food nutrition, supplement wisely when needed, and don’t forget lifestyle factors like stress, sleep, and gut health. These small, intentional actions add up, helping you feel more energized, balanced, and confident in your health.
Remember: you don’t have to wait until something “breaks” to take action. Being proactive about your nutrient status now is one of the most powerful ways to support your health, both today and for years to come.
✨ Ready to stop guessing and start feeling your best? Your body is unique, and so is the support you deserve. In a 1:1 consultation, we’ll take dive deep into your health, uncover what’s really going on beneath the surface, and create a personalized plan to help you reach your goals.
