⚠️ Safety Verdict: Use Caution (Bone & Kidney Concerns)
E338 (Phosphoric Acid) is approved but worth limiting. High intake (especially from cola drinks) linked to bone loss, kidney damage, and calcium depletion. Safe in small amounts, but chronic high consumption poses health risks.
🚨 Bone Health Warning (Cola Drinkers)
Regular cola consumption strongly linked to reduced bone density:
- Framingham Osteoporosis Study: Women drinking 3+ colas daily had 4% lower hip bone density
- Phosphoric acid interferes with calcium absorption
- May leach calcium from bones to balance phosphate levels
- Particularly concerning for women, children, and elderly
What is E338 (Phosphoric Acid)?
E338 is phosphoric acid (also called orthophosphoric acid), a mineral acid used as an acidifier and flavour enhancer.
How it works:
- Provides tangy, acidic taste in soft drinks
- Lowers pH – makes drinks more acidic
- Prevents bacteria/mold growth (preservative effect)
Why it's used:
- Distinctive cola taste – essential flavour in Coke, Pepsi
- Cheaper than citric acid
- Doesn't mask other flavours like citric acid does
Where is Phosphoric Acid Found?
Cola Drinks (Most Common):
- Coca-Cola, Pepsi, Dr Pepper (regular and diet)
- Other brown soft drinks
- Some energy drinks
Other Foods:
- Processed cheese
- Meat products (anti-discoloration agent)
- Some breakfast cereals
- Baking powder (some brands)
Non-Food Uses:
- Rust remover
- Dental cement
- Fertilizer production
Health Concerns
1. Bone Loss (Osteoporosis Risk)
Major concern – well-studied:
- Framingham Osteoporosis Study (2006): Cola drinkers had significantly lower bone mineral density
- 3+ colas daily = 4% lower hip bone density in women
- Effect seen in both regular and diet cola (not other sodas – suggests phosphoric acid, not sugar/caffeine)
Mechanisms:
- Calcium-phosphate imbalance: High phosphate intake disrupts calcium absorption
- Calcium leaching: Body may pull calcium from bones to balance phosphate levels
- Parathyroid hormone effects: Excess phosphate triggers hormone changes affecting bone
2. Kidney Damage (Chronic Kidney Disease)
- High phosphate intake strains kidneys
- May accelerate chronic kidney disease progression
- Studies link cola consumption to kidney stones
- People with kidney disease should strictly limit phosphoric acid
3. Tooth Enamel Erosion
- Highly acidic (pH 2.5 in cola) – erodes tooth enamel
- Combined effect with sugar worsens tooth decay
- Regular cola sipping causes chronic enamel damage
4. Cardiovascular Disease Risk
- High phosphate linked to blood vessel calcification
- May increase heart attack and stroke risk
- Studies show association with cardiovascular mortality
5. Digestive Issues
- Can cause stomach upset in sensitive people
- May worsen acid reflux/GERD
How Much Phosphoric Acid is Safe?
ADI (Acceptable Daily Intake): 70mg per kg body weight for all phosphates combined (including E338, E339, E340, E341, E450)
Problem: Modern diets often exceed this due to phosphate additives in processed foods + natural phosphates in meat/dairy.
One can of cola (330ml): Contains ~40-50mg phosphoric acid
- 1 cola = probably fine
- 3+ colas daily = approaching/exceeding recommended limits
Cola vs Other Soft Drinks
Why cola specifically problematic:
- Orange/lemon sodas use citric acid (E330) – safer for bones
- Cola uses phosphoric acid – bone loss link
- Studies show bone loss from cola, not other sodas
Who Should Avoid Phosphoric Acid?
❌ Must Avoid:
- People with chronic kidney disease – phosphates very dangerous
- Kidney stone sufferers – cola increases risk
⚠️ Consider Limiting:
- Women at risk of osteoporosis (especially post-menopausal)
- Children and teenagers – building bone mass critical
- Elderly – bone loss accelerates with age
- Anyone with acid reflux/GERD
- People with cardiovascular disease
Phosphoric Acid vs Citric Acid
| Aspect |
Phosphoric Acid (E338) |
Citric Acid (E330) |
| Used in |
Cola drinks |
Orange, lemon, lime sodas |
| Bone effects |
❌ Linked to bone loss |
✅ No bone concerns |
| Kidney effects |
⚠️ Strain on kidneys |
✅ Minimal concern |
| Safety |
⚠️ Limit intake |
✅ Very safe |
Regulatory Status
UK/EU: Approved with ADI of 70mg per kg body weight (for all phosphates combined)
US: FDA "Generally Recognized As Safe" (GRAS)
WHO: Recommends limiting phosphate additives due to health concerns
The Bottom Line
- ✅ Approved worldwide – considered safe at low levels
- ❌ Bone loss from cola consumption – well-documented
- ⚠️ Kidney strain – high intake harms kidneys
- ⚠️ Tooth enamel erosion – highly acidic
- ⚠️ Cardiovascular concerns – blood vessel calcification
- ⚠️ 3+ colas daily = health risk
- ✅ Essential cola flavour – hard to replace
Our recommendation: Limit cola consumption, especially if you're female, a child, elderly, or have kidney issues. Choose citric acid-based sodas (orange, lemon) over cola when possible. If drinking cola, limit to occasional consumption (1-2 per week max). Never use cola as daily hydration.
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Last updated: February 2026