Micronutrient Deficiency Diseases in Humans

• Iron. Main role in this lesson: Helps haemoglobin carry oxygen. A deficiency-related condition: Iron-deficiency anaemia.
• Iodine. Main role in this lesson: Needed to produce thyroid hormones. A deficiency-related condition: Iodine-deficiency goitre.
• Vitamin A. Main role in this lesson: Supports normal vision. A deficiency-related condition: Night blindness and other eye damage.
• Anaemia means that haemoglobin concentration or red-cell numbers are below normal. Goitre means an enlarged thyroid gland. Night blindness means difficulty seeing in dim light or darkness.

A matching table is not a diagnosis

• Iron deficiency can cause anaemia, but anaemia has other causes. Iodine deficiency can cause goitre, but thyroid enlargement also has other causes. A symptom alone does not establish the missing nutrient.

• Iron is needed to make haemoglobin. Haemoglobin is the oxygen-carrying protein in red blood cells. Too little available iron can reduce haemoglobin production.
• Iron-deficiency anaemia can cause tiredness, weakness and breathlessness. Mild cases may have no obvious symptoms. These symptoms are not specific enough for self-diagnosis.

Food supply and absorption both matter

• Lentils, beans, leafy greens and meat can provide iron. Iron from plant foods is generally absorbed less readily than iron from meat. The amount eaten is therefore not the same as the amount absorbed.

• No. Iron deficiency is a common cause, not the only cause. Other nutritional causes include deficiencies of folate and vitamin B12. Blood loss, infections, inflammation and inherited blood disorders can also cause anaemia.
• The body can lose iron through blood loss. Increased needs during growth or pregnancy can also contribute to iron deficiency. Different causes may occur together.

Keep the exam answer within its scope

• Iron is the expected nutrient in the retained question about India’s leading nutritional cause of anaemia. That answer does not mean every anaemic Indian is iron deficient. Haemoglobin testing measures anaemia, not its full cause.

• Iodine is needed to produce thyroid hormones. These hormones help regulate metabolism and support growth and development. The thyroid gland lies in the neck.
• When iodine supply is inadequate, the thyroid may enlarge while trying to maintain hormone production. The enlargement is called goitre. Iodine deficiency can also harm brain development, especially during pregnancy and early life.

Why use iodised salt?

• Iodised salt contains added iodine. It provides a way to deliver iodine through a commonly used food ingredient. Salt that looks white or clean is not necessarily iodised.
• Using iodised salt does not mean eating more salt. Deficiency prevention and limiting excess salt are compatible goals. More iodine is not always better; excess iodine can also disturb thyroid function.

• Vitamin A is needed for normal vision, including vision in dim light. Its deficiency can cause night blindness. Night blindness can be an early eye sign, not only a feature of the most severe deficiency.
• Xerophthalmia describes the eye changes caused by vitamin A deficiency. Severe eye damage can affect the cornea and lead to permanent blindness. Low vitamin A status and visible eye signs are not the same measurement.

Why are food variety and programme support useful?

• Different foods provide different nutrients. A diet adequate in calories can still lack vitamins or minerals. Targeted supplementation can help eligible groups alongside a varied diet.
• High-dose vitamin A supplements should not be taken as an unrestricted daily habit. Programme doses and treatment decisions need qualified health guidance. This lesson gives no personal supplement dose or treatment plan.

• The National Family Health Survey, or NFHS, reports population-level findings. NFHS-5 covered 2019–21. The figures below describe that survey period, not a live count of today’s patients.
• Children aged 6–59 months. NFHS-5 anaemia prevalence: 67.1%. Rounded recall figure: 67%.
• Adolescent girls aged 15–19 years. NFHS-5 anaemia prevalence: 59.1%. Rounded recall figure: 59%.
• All women aged 15–49 years. NFHS-5 anaemia prevalence: 57.0%. Rounded recall figure: 57%.
• The age ranges identify each denominator. “Children aged 6–59 months” does not include infants below six months. The adolescent-girl percentage does not describe all adolescents.

What does 67.1% mean?

• Imagine 1,000 children with the same survey age range and population profile. A prevalence of 67.1% corresponds to about 671 children with anaemia. This example illustrates a percentage; it is not a newly observed sample.
• The result is roughly two out of three children in that survey group. It does not mean 67.1% had laboratory-confirmed iron deficiency.

• Child anaemia prevalence increased between NFHS-4 and NFHS-5. The rounded comparison is 59% to 67%. NFHS-4 covered 2015–16, while NFHS-5 covered 2019–21.
• The official headline comparison figures are 58.6% and 67.1%. Their difference is 8.5 percentage points. A percentage-point difference subtracts the two percentages directly.

Does that prove fortification failed?

• No. The comparison describes a change, but it does not isolate its cause. Anaemia has nutritional and non-nutritional causes. Programme access, diet, infections and other circumstances can affect outcomes.
• Improved iodised-salt use addresses iodine supply. It cannot, by itself, explain a change in iron-related blood health. A programme’s existence also does not guarantee that every eligible person receives effective support.

• A historical district count is not a current national patient count. The older survey tally identified 337 of 414 surveyed districts as endemic for iodine-deficiency disorders. Government reporting retained that tally in 2017, after the 2015–16 period cited in earlier summaries.
• “Endemic” describes a condition occurring regularly in a population under the survey’s definition. In this tally, endemic means a total goitre rate above 5%. It does not mean every resident of those districts had goitre. Surveyed districts are not the same as every district in India today.

What did the 350 million estimate mean?

• A 2013 research paper estimated that 350 million Indians were at risk of iodine-deficiency disorders. The authors extrapolated from older data. The estimate combined 2009 salt-coverage information with 2011 population estimates. “At risk” does not mean diagnosed with the disorder.
• Keep that estimate attached to its historical inputs. Do not present it as a current count of people with iodine deficiency.

• No. These are historical global estimates for populations at risk. The 2009 global assessment used data from 1995–2005. Estimated low vitamin A status affected 33.3% of preschool children and 15.3% of pregnant women in those populations.
• The assessment measured low serum retinol, a biochemical indicator. The figures do not describe the percentage showing visible night blindness. They are also not current India-specific prevalence estimates.

Ask three questions about every statistic

• Identify the place, period and measured condition. “Global low vitamin A status” cannot be relabelled “India night blindness”. Keeping the original numbers is useful only when their meaning also stays correct.

• Fortification: adding nutrients to a food during production or processing.
• Supplementation: providing nutrients separately, such as through tablets or a measured liquid preparation.
• Dietary diversity: eating a range of foods that supply different nutrients.
• Iodising salt is fortification. Providing iron and folic acid tablets is supplementation. The methods can complement each other; they are not interchangeable treatments for every deficiency.

India’s programmes have a long history

• India launched the National Goitre Control Programme in 1962. The programme promoted iodine-deficiency control through iodised salt. It was renamed the National Iodine Deficiency Disorders Control Programme in 1992.
• The National Nutritional Anaemia Prophylaxis Programme began in 1970. It included iron and folic acid support for vulnerable groups. India’s national vitamin A prophylaxis programme also began in 1970.
• Prophylaxis means prevention rather than waiting for an illness to develop. A preventive programme does not prove that deficiency has disappeared.

• No. Salt-test results and a person’s iodine status measure different things. NFHS-4 found iodised salt in 93.1% of tested households during 2015–16. The test identified iodine presence, not every person’s dietary intake.

Why is the older 71.6% comparison misleading?

• The NFHS-2 salt table for 1998–99 listed 28.4% as not iodised. Subtracting 28.4% from 100% gives 71.6%. However, that remainder includes missing test results.
• The table separately listed 21.6%, 16.8% and 32.6% at increasing iodine-test levels. Their sum is 71.0%, allowing for rounded values. The 15 and 30 parts-per-million categories together give 49.4%.
• Those categories distinguish iodine presence from adequate iodisation under the older survey measure. Parts per million, or ppm, describes concentration. Comparing unlike indicators can exaggerate the apparent improvement.
• The earlier infographic combines several historical figures. Use the dated definitions in this lesson when interpreting its salt and vitamin A labels.

• Adding a nutrient cannot resolve every cause of poor health. A person may have inadequate intake, poor absorption or increased nutrient needs. Infection and blood loss can also contribute to anaemia.
• Food variety supports several nutrient needs at once. Targeted supplementation supports eligible groups. Testing and treatment help address the actual cause of illness.
• These approaches can work together. A child with night-vision difficulty should not be diagnosed from an exam matching table. A qualified health professional must assess symptoms and appropriate treatment.

• Anaemia Mukt Bharat uses prophylactic iron and folic acid supplementation. Iron and folic acid are often abbreviated IFA. Replacing iron with calcium changes the intervention.
• The UPSC CSP 2023, Q52 reference tests the programme’s interventions. UPSC means Union Public Service Commission. CSP means Civil Services Preliminary Examination.

Match the exact programme wording

• Calcium is a useful nutrient, but it is not the named substitute for iron in this intervention. The programme also includes deworming, behaviour-change communication, testing and treatment. It addresses non-nutritional causes of anaemia as well.
• Do not infer a complete answer combination from the iron-versus-calcium trap alone. Read every statement in the examination question.

• Vitamin C deficiency can cause scurvy. Bleeding gums can occur in scurvy. Vitamin C supports collagen formation and wound healing.
• Vitamin D deficiency can cause rickets in children. Rickets affects growing bones. These pairs broaden revision without replacing this lesson’s iron, iodine and vitamin A focus.