Human Nutrition 3(3+0)

Lesson 47 : Assessment of Nutritional Status

Biochemical methods

Biochemical methods involve estimating the level of the nutrient in blood or urine. These methods yield reliable data regarding the nutritional status of the individual with respect to the specific nutrient estimated. Biochemical studies which have been used in nutrition surveys are listed in table.

Advantages of Biochemical Method

• Useful in the detection of early changes in body metabolism & nutrition before the appearance of overt clinical signs.
• Precise, accurate and reproducible.
• Useful to validate data obtained from dietary methods for example comparing salt intake with 24-hour urinary excretion.

Limitations of Biochemical Method

• Time consuming
• Expensive
• Cannot be applied on large scale
• Needs trained personnel & facilities

Table: Biochemical parameters suitable for assessment in nutrition surveys

SNo	Nutrient deficiency	Constituents in blood	Constituents in urine
1	Protein	Total serum protein Serum albumin	Total urea, Total creatinine Hydroxyproline.
2	Vitamin A	Serum vitamin A Serum carotene	---
3	Vitamin D	Serum inorganic P Serum alkaline phosphatase in infants and weaned infants.	---
4	Ascorbic acid/vit C	Serum ascorbic acid W.B.C ascorbic acid	Urinary ascorbic acid Load test
5	Thiamine	R.B.C transketolase activity Blood pyruvate	Urinary thiamine Load test
6	Riboflavin	R.B.C. riboflavin	Riboflavin in urine
7	Niacin	---	Load test /urinary excretion of N-methyl nicotinamide pyridine, load test
8	Iron	Haemoglobin in blood Serum iron
9	Iodine	Protein bound iodine	Urinary iodine