A major cause for iron deficiency anaemia is the poor dietary intake. Deferioxamine, an iron-chelating agent, which has possible anti-inflammatory properties, causes haemoglobin and serum iron levels to increases. This shows that iron stores are needed within the body and an adequate dietary intake to meet the recommended intakes should be encouraged, even though there is no evidence for additional routine supplementation for patients with RA. Studies have examined the effect of calcium supplementation on bone mineral density among subjects taking corticosteroids. A study of calcium combined with vitamin D3 in RA patients taking low-dose corticosteroids demonstrated a reduction in bone mineral density loss in both the spine and trochanter, but not the femoral neck. However, no change was seen in BMD with calcium and vitamin D3 supplementation in RA patients not receiving corticosteroids. Therefore, there is little evidence to support calcium and vitamin D supplementation in corticosteroid receiving RA patients. Lastly, low levels of serum zinc have been reported in patients with RA which may be caused by elevated IL-1b levels. However, Zinc supplementations yield contradictory results and at present do not support a therapeutic use of zinc. Food containing high source of fluoride to help treat Rheumatoid Arthritis include tomatoes, oranges, bell peppers and grapefruit, which you should eat in moderation. Iron can be incorporated into the diet by eating seafood, spinach, and peas. Moderate amounts of calcium should be included into the diet by having milk, cheese, dairy products, curly kale, okra, bread and fortified flour products such as cereals.
With these parameters, DAS28 is calculated as:
  
    
      
        D
        A
        S
        28
        =
        0.56
        ×
        
          
            T
            E
            N
            28
          
        
        +
        0.28
        ×
        
          
            S
            W
            28
          
        
        +
        0.70
        ×
        ln
        ⁡
        (
        E
        S
        R
        )
        +
        0.014
        ×
        S
        A
      
    
    {\displaystyle DAS28=0.56\times {\sqrt {TEN28}}+0.28\times {\sqrt {SW28}}+0.70\times \ln(ESR)+0.014\times SA}
  
From this, the disease activity of the affected person can be classified as follows:
It is not always a reliable indicator of treatment effect.