Most people think of nutritional deficiencies as something that happens in developing countries, or to people on severely restricted diets. The reality is more complicated. UK population studies consistently show suboptimal intake of magnesium, vitamin D, iron, zinc and vitamin B12 across broad swathes of the population — particularly in older adults, those who are pregnant, vegans and vegetarians, and people with absorption issues.
The body often signals these gaps through everyday symptoms that are easy to dismiss. This article explores 10 such signals — and the nutrient most commonly associated with each. These are not diagnostic tools. The symptoms listed each have many possible causes, the majority of which are not nutritional. Use this as a starting point for a conversation with your GP — not as a self-diagnosis guide.
Sign #1
Clicky Jaw or Teeth Grinding
That clicking, clenching or grinding — sometimes called bruxism or TMJ dysfunction — has multiple causes including stress, sleep disorders, dental issues and jaw alignment. But magnesium is increasingly discussed in this context, and for good reason: magnesium plays a central role in muscle relaxation by competing with calcium at the cellular level. When magnesium is low, muscles — including the small, powerful jaw muscles — may struggle to fully relax.
Approximately 50% of adults don't meet the recommended dietary intake for magnesium, according to population nutrition data. For those whose jaw clenching is linked to muscular tension or stress, low magnesium may be a contributing factor worth exploring with a GP.
Supplement option: Magnesium Bisglycinate 650mg — chelated form, gentle on digestion
Authorised claim: Magnesium contributes to normal muscle function ✅
Many causes — see your GP before supplementing, especially if on medication or with kidney concerns.
Sign #2
Aching Feet First Thing in the Morning
That sharp or aching pain in the heel or arch when you take your first steps — often attributed to plantar fasciitis — has structural, mechanical and inflammatory causes as its most common explanation. However, low Vitamin D is occasionally discussed as a contributing factor in musculoskeletal pain and bone discomfort, including in the feet. Research has linked vitamin D deficiency to generalised musculoskeletal pain, and Vitamin D is required for calcium absorption and bone mineralisation.
In the UK, the NHS recommends Vitamin D supplementation for most adults throughout autumn and winter as dietary sources are limited and sunlight is insufficient. It's one of the most prevalent deficiencies in the UK population.
Supplement option: Vitamin D3 + K2 Capsules
Authorised claim: Vitamin D contributes to maintenance of normal bones and teeth ✅
Aching feet have many causes — see your GP. Avoid high-dose Vitamin D without medical supervision.
Sign #3
Frequent Muscle Cramps
Night leg cramps, calf cramps during exercise or random muscle spasms are common complaints. Dehydration, overexertion, poor circulation and medication side effects are all common causes. But low magnesium is one of the best-established nutritional associations with muscle cramps. Case reports published in the Canadian Family Physician documented resolution of severe muscle cramps following magnesium supplementation in documented deficiency.
Magnesium regulates calcium flow in and out of muscle cells — calcium triggers contraction, magnesium supports relaxation. When magnesium is depleted, this cycle can become dysregulated. Low potassium is also associated with cramping, particularly in those on diuretics. Worth discussing both with your GP.
Supplement option: Magnesium Bisglycinate 650mg
Authorised claim: Magnesium contributes to normal muscle function ✅
Frequent cramps warrant a GP review — other causes including vascular and neurological should be ruled out.
Sign #4
Cracked Corners of the Mouth
Angular cheilitis — painful cracking, soreness or ulceration at the corners of the mouth — is most commonly caused by fungal or bacterial infection, ill-fitting dentures, excess saliva or skin conditions. However, nutritional deficiencies have been documented as a contributing factor in some cases, particularly low riboflavin (Vitamin B2), Vitamin B12, iron and folate. These nutrients are involved in maintaining the health of mucous membranes and the integrity of skin at the mouth corners.
This is most commonly seen in older adults, vegans and vegetarians (particularly for B12 and iron) and those with absorption difficulties such as Crohn's disease or coeliac disease.
Supplement option: Iron Complex 14mg if iron-related (only after GP confirmation of deficiency)
Authorised claim: Iron contributes to normal formation of red blood cells ✅
Angular cheilitis is usually fungal — see your GP or dentist. Do not self-supplement iron without a blood test confirming deficiency.
Sign #5
Feeling Tired All the Time
Fatigue is one of the most common presenting complaints in general practice — and one of the most non-specific. Thyroid issues, sleep disorders, depression, anaemia, infection and dozens of other conditions can cause persistent tiredness. From a nutritional standpoint, iron deficiency anaemia is one of the most prevalent and well-established nutritional causes of fatigue worldwide, and is particularly common in women of reproductive age, pregnant women, and those with diets low in haem iron. Vitamin D deficiency and low B12 are also frequently associated with low energy and fatigue.
The important distinction: supplementing iron without a confirmed deficiency is not recommended and can be harmful. This is one sign where a simple blood test from your GP is genuinely the right first step.
Supplement option: Iron Complex 14mg — only where deficiency is confirmed by GP
Authorised claim: Iron contributes to reduction of tiredness and fatigue ✅ (where iron deficiency is present)
⚠️ Do not supplement iron without a blood test. Excess iron is harmful. Always see your GP for persistent fatigue — many serious conditions need to be ruled out.
Sign #6
Pins and Needles
Occasional pins and needles from sitting awkwardly are normal. Persistent, recurring or progressive tingling — particularly in the hands and feet — is different and should always be investigated medically. Nerve compression, poor circulation, diabetes and multiple sclerosis are all possible causes. From a nutritional standpoint, Vitamin B12 deficiency is the most well-established nutritional cause of peripheral neuropathy — tingling, numbness and nerve sensations in the extremities. B12 is essential for the maintenance of myelin — the protective sheath around nerve fibres.
B12 deficiency is particularly common in vegans and vegetarians, older adults and those on long-term metformin or proton pump inhibitors. A blood test will confirm whether B12 levels are low.
Supplement option: Vitamin B12 (methylcobalamin form preferred for absorption)
Authorised claim: Vitamin B12 contributes to normal functioning of the nervous system ✅
⚠️ Persistent pins and needles need GP investigation — do not assume nutritional cause. B12 deficiency severe enough to cause neuropathy often requires treatment beyond standard supplementation.
Sign #7
Poor Night Vision or Slow Adaptation to Darkness
Difficulty seeing in low light, or noticing it takes longer than usual to adjust when moving from bright to dark environments, has several causes including refractive errors and eye conditions. However, Vitamin A deficiency is the most well-documented nutritional cause of night blindness (nyctalopia). Vitamin A is required for the production of rhodopsin — the photoreceptor pigment in the rod cells of the retina that enables vision in low light. In severe and prolonged deficiency, the effects can be irreversible.
True Vitamin A deficiency is uncommon in the UK general population, but can occur in those with severe fat malabsorption, liver disease, or very restrictive diets. Note: Vitamin A is a fat-soluble vitamin and excess intake can be toxic — safe intake levels must not be exceeded.
Authorised claim: Vitamin A contributes to maintenance of normal vision ✅
⚠️ Vitamin A toxicity is a real risk — do not exceed safe upper limits (3,000 mcg RAE/day for adults). Always see an optician or GP for vision changes before considering supplementation. Pregnant women should avoid high-dose Vitamin A entirely.
Sign #8
Slow Wound Healing
Cuts and grazes that seem to take longer than expected to heal can reflect circulation issues, blood glucose control problems (including undiagnosed diabetes), immune function or medication side effects. From a nutritional perspective, zinc is the most consistently studied micronutrient in wound healing research. Zinc is involved in protein synthesis, cell division, immune function and the inflammatory response — all components of the wound healing cascade. Vitamin C is also important, as it is required for normal collagen formation (authorised EU/UK claim) which is central to tissue repair.
Zinc deficiency is more common than many realise, particularly in older adults, those with gastrointestinal disorders and those on plant-based diets where zinc bioavailability from food is lower.
Supplement option: Triple Zinc + Copper Tablets · Liposomal Vitamin C ⚠️ contains soy
Authorised claims: Zinc contributes to normal protein synthesis ✅ · Vitamin C contributes to normal collagen formation ✅
Slow wound healing should be discussed with your GP — particularly to rule out diabetes or circulatory problems. Do not take zinc long-term without copper to maintain balance.
Sign #9
Bleeding Gums
Gums that bleed when brushing are most commonly a sign of gingivitis — inflammation caused by plaque buildup — and the primary response is improved dental hygiene and a visit to the dentist, not supplementation. However, Vitamin C deficiency has a well-established historical and clinical association with gingival bleeding — a feature of scurvy in its severe form. At subclinical levels, low Vitamin C may affect gum tissue integrity and vascular health, as Vitamin C is required for normal collagen formation (authorised EU/UK claim). Vitamin C also contributes to normal immune function — another relevant mechanism for gum health.
True scurvy is rare in the UK. But suboptimal Vitamin C intake is common, particularly in smokers (who have higher Vitamin C requirements), older adults and those with restricted diets.
Supplement option: Liposomal Vitamin C Capsules ⚠️ contains soy
Authorised claims: Vitamin C contributes to normal collagen formation ✅ · normal immune function ✅
See your dentist first — bleeding gums are most often a dental hygiene issue. Vitamin C supplementation is not a substitute for dental care.
Sign #10
Brittle or Peeling Nails
Nails that chip, peel, break easily or grow slowly are most commonly explained by repeated exposure to water, chemicals, nail products or drying environments. Thyroid conditions are a medical cause worth ruling out. From a nutritional perspective, iron deficiency has a recognised association with nail changes including koilonychia (spoon-shaped nails) and general nail brittleness. Biotin is widely marketed for nail health, but the evidence base in healthy people without deficiency is limited — most published studies used high doses in people with specific nail conditions. Zinc also has an authorised EU/UK claim for maintenance of normal nails.
The honest position: if your nails are brittle, check your iron levels with your GP before supplementing. Biotin won't hurt at standard doses, but the evidence it helps healthy nails is thin. Address the environment your nails are exposed to first.
Supplement option: Iron Complex 14mg (if deficient only) · Triple Zinc + Copper Tablets
Authorised claims: Zinc contributes to maintenance of normal hair, skin and nails ✅ · Iron contributes to normal formation of red blood cells ✅
Evidence for biotin in people without deficiency is limited. See your GP to check iron and thyroid before supplementing.
Quick Reference Summary
| Body Sign | Possible Nutritional Link | Authorised Claim? | GP First? |
|---|---|---|---|
| Clicky jaw / teeth grinding | Magnesium | ✅ Muscle function | Yes |
| Aching feet in morning | Vitamin D | ✅ Normal bones | Yes |
| Frequent muscle cramps | Magnesium, Potassium | ✅ Muscle function (Mg) | Yes |
| Cracked corners of mouth | B2, B12, Iron, Folate | ✅ Iron (red blood cells) | Yes |
| Tiredness all the time | Iron, Vitamin D, B12 | ✅ Iron (tiredness) | ⚠️ Essential |
| Pins and needles | Vitamin B12 | ✅ Nervous system (B12) | ⚠️ Essential |
| Poor night vision | Vitamin A | ✅ Normal vision (A) | ⚠️ Essential |
| Slow wound healing | Zinc, Vitamin C | ✅ Zinc (protein synthesis) | Yes |
| Bleeding gums | Vitamin C | ✅ Collagen (Vit C) | Yes (dentist) |
| Brittle nails | Iron, Zinc, Biotin | ✅ Zinc (nails) · Iron (RBC) | Yes |
The Honest Bottom Line
Every symptom on this list has multiple possible explanations. Most are not nutritional. The point of this article is not to suggest you self-diagnose or self-supplement — it's to raise awareness that everyday complaints sometimes have nutritional associations that are worth exploring with your GP.
A simple blood test can confirm or rule out iron deficiency, low B12, low vitamin D, low zinc and more. That is always the right starting point before buying any supplement — particularly for iron, where supplementing without confirmed deficiency can cause harm.
At Charge Products we make it a point to tell you when the evidence is strong, when it's emerging, and when a symptom needs a GP before it needs a supplement. All products mentioned in this article are food supplements — not medicines.
📚 Research References
Educational context only — not health claims. All authorised claims cited above apply to the specific nutrients under retained UK Regulation 1924/2006.
Garrison et al. (2012) — Magnesium for Muscle Cramps · Cochrane Database
PubMed 22258976 →Schwalfenberg & Genuis (2017) — Magnesium in Clinical Healthcare · Scientifica
PubMed 29093983 →Holick (2007) — Vitamin D Deficiency · New England Journal of Medicine
PubMed 17634462 →Camaschella (2015) — Iron Deficiency Anaemia · New England Journal of Medicine
PubMed 25946282 →Stabler (2013) — Vitamin B12 Deficiency · New England Journal of Medicine
PubMed 23388003 →Lansdown et al. (2007) — Zinc in Wound Healing · Wound Repair and Regeneration
PubMed 17244314 →
