1. Basic Biochemistry: Purines in Food Dr Liz Carrey UCL Institute of Child Health

2. Gout Primary gout: excess uric acid in circulation, from purines taken in the diet

3. Nucleic acids DNA: genetic information RNA: many roles

4. A mammalian cell

5. Mitochondria

6. Purines in the diet 1 DNA and RNA are highest in cells that are multiplying, tissues that are regenerating Mitochondria are most numerous in energy-producing cells (e.g. muscle) Mitochondria contain ATP and DNA

7. N N N N NH 2 O O (phosphate) 3 OH ATP energy purinergic signalling RNA, DNA cofactors (NAD etc) cAMP and AMP phosphate donor O O phosphate OH N N N N O IMP umami

8. Purines in the diet 2 DNA, RNA, nucleotides and bases are digested in the gut No purines are absorbed from the diet Uric acid is excreted directly from the gut (1/3) or via kidneys, in the urine (2/3)

9. Purines uric acid allantoin N N NHNH N NH 2 N N N O H H H O O H N N H O N N H H O H N O H X

10. uric acid N N N O H H H O O H N xanthine N N NHNH N O O Less soluble at acid pH Forms kidney stones if not excreted Excess may be deposited in joints and under the skin

11. uric acid allantoin N N N O H H H O O H N N H O N N H H O H N O H xanthine N N NHNH N O O ALLOPURINOL URICASE

12. High-purine foods Red meat (mitochondria, ATP) Organ meats (regenerating tissue: DNA) Sea food (energy, growth) Beer (yeast, rapidly multiplying: DNA) Asparagus, cauliflower (multiplying: DNA) Wheat germ, cereals, seeds (DNA)

13. Purine-rich meat, seafood and beer increase the risk of gout in men Choi et al, 2004: NEJM & Lancet Prospective 12-yr study of men aged 40 – 75, health professionals in USA 5.6% already had gout symptoms Of remaining 47,150 gout developed in 730, incidence of 1:1000 per year

14. The risk of gout in men Relative risk for meat-eaters 1.41; for high seafood consumption 1.51 Beer: RR 1.49 per 12oz/day No relationship to high-purine vegetables? Highest dairy intake, RR 0.56

15. Low-purine foods White bread Dairy products (milk, cheese, yogurt) Sugar and confectionery Most fruit and salad vegetables Fruit juices Water ? ? ? ?

16. Giles Corens dinner at Bonds, 5 Threadneedle Street Salad of smoked eel Roosters testicles on a bed of sweetbreads and kidney Sea bass with frog leg aïoli and 2 fritters of bone marrow Vegetables? Dessert? £100 for two without wine

17. Purines in the diet 3 Lower proportion of high-purine foods More dairy products (low fat!) Less fruit juice and fructose Smaller portion sizes More water – to dilute the urine