5 Nutrients Women in the UK Are Almost Always Deficient In - And Why It Matters for Energy, Hair and Glow

If you've been eating reasonably well, taking care of yourself, and still feeling flat, tired, or noticing your hair isn't quite what it was, you're not imagining it. The gap between effort and results is real, and for many women in the UK, it has a nutritional explanation.

The problem is that most content about nutrient deficiencies is written for a US audience. It references US dietary surveys, US fortification rules, and a US climate. None of that maps accurately onto life in Britain, where the weather, the food supply and the public-health data tell a different story.

The UK-specific factors most wellness content overlooks:

• The UK has no mandatory iodine fortification in staple foods, unlike the US

• Between October and early March, UK sunlight cannot trigger vitamin D synthesis in the skin at all

• The National Diet and Nutrition Survey (NDNS) 2019-2023, published by the Office for Health Improvement and Disparities, is the most comprehensive picture of what UK adults are actually eating and absorbing

• Women of reproductive age consistently show up as a higher-risk group across multiple nutrients in UK survey data

This article focuses on five nutrients where UK evidence, not generic wellness advice, points to a genuine and widespread shortfall. For each one, you'll find the UK data, the symptoms worth knowing about, the food sources that help, and where supplements may be a sensible addition.

Symptoms alone are not a diagnosis. If you have persistent concerns, a GP can run blood tests to check your actual levels.

1. Vitamin D: the obvious UK problem that still gets underestimated

Vitamin D is the most straightforward entry on this list, and yet it still gets underestimated. The UK's latitude means that from October to early March, there is simply not enough UVB radiation in sunlight for the skin to produce vitamin D at all. Diet alone is rarely enough to compensate.

UK data: According to the NDNS 2019-2023 report, 18% of adults aged 19 to 64 had low vitamin D status. In winter months, that figure rose to 31%. This is not a fringe problem. It is a seasonal reality for a significant proportion of the population.

Public Health England and NICE have both advised that everyone in the UK should consider taking 10 micrograms of vitamin D daily during autumn and winter. For some groups, year-round supplementation is recommended.

Who may need year-round attention

• Women with darker skin tones, as melanin reduces vitamin D synthesis from sunlight

• Those who spend most of their time indoors

• Anyone who covers most of their skin when outdoors

Food sources (limited, but worth including)

• Oily fish: salmon, mackerel, sardines

• Eggs (particularly the yolk)

• Fortified foods: some cereals and plant milks

Why it matters for how you feel: Vitamin D supports muscle function, immune response and general wellbeing. Low levels are associated with persistent fatigue and low mood, which is why many women notice a dip in how they feel through the darker months.

2. Iron: the nutrient most likely to show up in energy and hair concerns

Iron is the nutrient women are most likely to fall short on, and the symptoms are the ones most likely to be dismissed as just being tired or stressed. Menstruation raises iron requirements significantly, and UK survey data shows that a large proportion of women are not meeting them through diet alone.

According to earlier NDNS rolling programme data, 25% of women aged 19 to 64 had iron intakes below the Lower Reference Nutrient Intake (LRNI). The UK Government Dietary Recommendations set the reference nutrient intake for premenopausal women at 14.8mg per day, nearly twice the amount required by men of the same age.

It is worth distinguishing between three different points on the spectrum: dietary shortfall (not eating enough iron), low ferritin (depleted iron stores, even without anaemia), and iron deficiency anaemia (a more significant clinical state). Women can experience symptoms at the ferritin stage, before anaemia develops.

Common symptoms linked to low iron (per NHS guidance)

Good dietary sources of iron

• Red meat and offal (highest bioavailability)

• Lentils, chickpeas, kidney beans

• Dark leafy greens: spinach, kale

• Tofu and fortified breakfast cereals

• Pumpkin seeds and dried apricots

Absorption tip: Pairing plant-based iron sources with vitamin C improves absorption. Avoid tea or coffee with iron-rich meals, as tannins reduce uptake.

3. Iodine: the overlooked one UK women rarely hear about

Iodine rarely appears in mainstream wellness content, which is precisely why it belongs on this list. Unlike the US, the UK does not fortify salt with iodine. The primary dietary sources are dairy products and fish, which means women who eat less of either are at higher risk of falling short.

Why iodine matters more in the UK than most listicles admit: The NDNS 2019-2023 report found that women of childbearing age (16 to 49 years) had insufficient iodine status, with urinary iodine concentration below the 100 micrograms per litre threshold. Earlier NDNS data found the median for this group was 98 micrograms/L, with 21% falling below 50 micrograms/L. Iodine status has also been declining: between 2013 and 2023, urinary iodine concentration decreased by 25% in adults aged 19 to 64.

Iodine is essential for the production of thyroid hormones, which regulate metabolism and energy. When iodine intake is consistently low, thyroid function can be affected, and the result is often a cluster of symptoms that look very similar to other deficiencies: fatigue, sluggishness, difficulty concentrating and feeling generally run-down.

The NHS advises that adults need 140 micrograms of iodine daily, and notes that people following a strict vegan diet who avoid fish should consider an iodine supplement.

Main food sources of iodine in the UK diet

• Cow's milk and dairy products

• White fish and seafood

• Some plant milks (check for iodine fortification on the label, as many are not)

• Eggs

4. Folate: not just a pregnancy nutrient

Folate tends to be discussed almost exclusively in the context of pregnancy, which means most women of reproductive age never give it a second thought. UK data suggests they probably should.

The NDNS 2019-2023 report found that 83% of women aged 16 to 49 had a red blood cell (RBC) folate concentration below 748 nmol/L, the threshold below which there is an increased risk of a pregnancy affected by neural tube defects. That figure has been consistently high across multiple rounds of the NDNS. This is a public-health concern that most beauty and wellness brands have never addressed.

Three things worth knowing about folate and UK women

1. Folate supports normal cell division and DNA synthesis, processes that matter well beyond pregnancy for energy, tissue repair and overall cellular health

2. UK government guidance recommends women of childbearing age take a 400 microgram folic acid supplement daily until the 12th week of pregnancy, precisely because dietary intake is so often insufficient

3. The gap is consistent across income levels, though lower-income groups tend to have worse folate status overall, according to NDNS analysis

Who should pay particular attention

• Women aged 16 to 49, especially those who may become pregnant

• Those eating few leafy greens, pulses or fortified foods

• Anyone following a restrictive diet

Good dietary sources: dark leafy greens, broccoli, chickpeas, fortified breakfast cereals, liver (avoid in pregnancy).

5. Magnesium: a common intake gap, handled honestly

Magnesium is worth including on this list, but with some care around the language. Unlike the nutrients above, magnesium deficiency is not straightforwardly measurable from a standard blood test, because most magnesium is stored in bone and tissue rather than in the blood. What UK data does show, consistently, is that mean magnesium intakes are below the Reference Nutrient Intake (RNI) across most adult age groups, and substantial proportions fall below the Lower Reference Nutrient Intake.

The UK Government Dietary Recommendations set the RNI for adult women at 270mg per day. NDNS data from years 1 to 4 found that mean intakes of magnesium were below the RNI in all adult age groups, with the NDNS noting this as a concern alongside potassium and selenium.

What low magnesium intake may be associated with

• Tiredness and low energy

• Difficulty sleeping

• Muscle tension or cramps

• Feeling more reactive to stress than usual

These are common, non-specific symptoms, and they are not proof of magnesium deficiency on their own. The honest framing is that many women are not consistently hitting the recommended intake from food, and that this may contribute to how they feel day to day.

Food sources to prioritise

• Nuts and seeds, particularly pumpkin seeds and almonds

• Dark chocolate (70%+)

• Whole grains: brown rice, oats, wholemeal bread

• Leafy greens: spinach, Swiss chard

• Legumes: black beans, edamame

What to do if this sounds familiar

Reading a list of symptoms is not a diagnosis, and it is worth being clear about that. But if several of the patterns above resonate, there are some sensible steps to take.

1. Start with diet. Look honestly at whether you are regularly eating iron-rich foods, oily fish, dairy, leafy greens and whole grains. Many intake gaps come down to routine rather than anything more complex.

2. Note your symptoms and how long they have been present. If fatigue, hair loss or persistent low mood have been ongoing for weeks or months, it is worth speaking to your GP. A simple blood test can check iron, ferritin and vitamin D levels.

3. Consider supplementation where UK guidance supports it. Vitamin D during autumn and winter is recommended for everyone. Folic acid is recommended for women of childbearing age. For other nutrients, a well-formulated daily supplement can help close routine intake gaps, particularly if your diet is varied but not always consistent.

A note on supplements: They work best as a complement to a reasonable diet, not a replacement for one. If you are looking for a simple way to support your daily intake across multiple nutrients, Nurtured Club's supplements are formulated with this kind of everyday support in mind.