Dr. R K Bhardwaj, Himani Sharma
The World Iodine Deficiency Day or Global Iodine Deficiency Disorders Prevention Day is observed every year on 21st of October. This year the theme is:Nurturing Health with Iodine: Deficiency Prevention for All with the moto to raise awareness to prevent health issues caused by iodine deficiency and its devastating effects on brain development.
Iodine is an essential micro-mineral required for normal thyroid function, growth, and development as it is essential for the synthesis of the thyroid hormones L-triiodothyronine and thyroxine which, have a role in thermoregulation, increasing cellular respiration and energy generation and have widespread effects on intermediary metabolism, growth, development, reproduction, muscle function, immune defence and circulation.

World Iodine Deficiency Day

Iodine deficiency (ID) can result in multifarious health and developmental disorders known as Iodine Deficiency Disorders (IDDs).These disorders may result in preventable mental retardation and can cause miscarriage, hypothyroidism, stillbirth, impaired mental function, congenital anomalies and iodine-induced hyperthyroidism or hypothyroidism. The consequences of ID range from loss of intelligence quotient (IQ) to cretinism. The main visible sign of severe ID is goitre and learning disability in mild deficiency.There is IQ level of 13 points difference between iodine deficient and normal children. One point increase in IQ associated with 0.11% increase in GDP.
Nutritional iodine deficiency in livestock is the leading cause of thyroid gland disorders/goitre. It generally occurs in farm animals wherever human goitre is endemic. Goat is considered as indicator species of iodine deficiency because of browsing habits and less ingestion of soil compared to other grazing animals.In companion animals like dog, not enough iodine can cause hypothyroidism which leads to stunt growth, increased thirst, rough coat, alopecia, lethargy and weight gain. Some people even report that their pets experience a change in behaviour, usually depression or aggression.
Statistics
IDDs are a major public health concern worldwide. The prevalence of self-reported goitre or thyroid disorder in National Family Health Survey IV [NFHS IV (2015-2016)] was 2.2%, which has increased to 2.9% in NFHS-V (2019-2021).It has been estimated that more than 200 Million people in India and 1.5 billion people worldwide are susceptible to IDDs with approximately 71 million persons presently suffering from goitre and other IDDs. IDDs can affect every stage of life, but most vulnerable age group is between 6 and 12 years and these disorders together constitute the single largest preventable cause of brain damage leading to learning disabilities and psychomotor impairment.
A study of 2023 conducted by Department of Community Medicine, GMC, Srinagar, UT of J&K to determine the prevalence of goiter among school-aged group of 6-12 years in district Ganderbal of Kashmir valley. Out of 2700 children examined, Grade-1 goiter was found in 90 (3.3%) children and Grade-2 goiter was found in 6 (0.3%) with a total goiter rate of 3.6%. On analyzing the urine samples, about 19.1% of the children had mild to moderate iodine deficiency. Iodine deficiency was a serious concern in all of Jammu’s neighbouring districts except Jammu. Females had a greater frequency of goitre than males (16.12 percent vs 10.10 percent).
Powdered salt was also found to be consumed by 75% of the people in Jammu, with more than 98.5 percent of powdered salt having an iodine level of more than 15 ppm. A study published in the Indian Journal of Medical Research (IJMR) in 2013 indicated that the entire population of India is at risk of IDD due to the soil of the subcontinent lacking in iodine. As a result, the wide variety of grains, lentils, fruits, vegetables, nuts and seeds grown in India do not have sufficient amounts of iodine. No matter what type of diet you have in India, the amount of iodine in it is, therefore, very low and needs to be supplemented with the use of salt that is fortified with iodine.
A study published in The Journal of Nutrition in 2023, showing the insights from the India Iodine Survey, 2018-19 indicated that at the national level, the household coverage of edible salt with adequate iodine (content ?15 parts/million) was 76.3%. At the sub-national level, the coverage varied, with 10 states and 3 UTs achieving Universal Salt Iodization and 11 states and 2 UTs falling below the national average, with the highest among all the states and UTs, being Jammu and Kashmir and the lowest being Tamil Nadu.
Iodine requirement and sources
Iodine is not synthesised in our body and requirement can be met through the food and water that we ingest. According to WHO guidelines, a daily iodine intake of 150 microgram is required to prevent IDDs and this can be achieved by using adequately iodised salt (15ppm) of iodine.
As per expert member of Indian Dietetic Association, the average salt intake in Indian homes range from 5-10g/day, of which, 30% is lost during cooking and 70% is absorbed, providing an average amount of 70µg/day. Apart from salt, milk is another source of iodine with 303µg/litre. Half a litre of milk is the minimum quantity needed by adults to obtain the 150µg recommended dietary allowance. Seafood such as tuna, shrimps, cod, scallops and egg yolks are also considered excellent sources of iodine along with vegetables and fruits like sweet potato, onion, spinach, banana, and cantaloupe contain adequate iodine.
Iodine content of plant varies with species, strains, climatic and seasonal conditions, and chemical fertilizer supplemented to plants. Cereals, wheat bran, and oil cakes are poor in iodine, whereas straws and green fodders contain marginally adequate content of iodine as per requirement by livestock. Stage of maturity and cutting time significantly affect the iodine content of the fodder. Iodine content of fodder decreases with fall in environment temperature and vice versa. The excessive use of chemical fertilizers like DAP and potash decreases the uptake of iodine from soil; conversely, supplementation of seaweeds in soil will increase the iodine content of soil.The relationship of iodine content of soil, plant and animal products like milk has got importance here. If soil is low in iodine, plants/grasses growing on such soil will be iodine deficient and animal grazing and yielding milk will also be low in iodine.Being, milk is good source of iodine, instead of normal intake of such milk, body iodine requirement will not be met and signs of iodine deficiency and hypothyroidism will develop. To achieve an adequate iodine status during the pregnancy, the WHO currently recommends a dietary intake of 250µg of iodine daily. Iodine shortage during pregnancy can lead to stillbirths, spontaneous abortions and congential abnormalities including cretinism, some of which are extremely dangerous.
Iodine in Environment
In general, sandy soils are low in iodine. High clay content and high pH of soil interfere with the iodine uptake by plants growing on such soils. Iodine deficiency in large areas of the world is associated with iodine cycle in nature. Iodine occurs in the soil and the sea as iodide. Iodide ions are oxidized by sunlight to elemental iodine which is highly volatile. The concentration of iodide in seawater and air is about 50 ?g/l and 0.7 ?g/m³, respectively. Iodine in atmosphere is returned to the soil by rain and snow which has a concentration in the range of 1.8-8.5 ?g/l. The return of iodine is slow and small in amount as compared to the original loss, and repeated flooding further decreases iodine in the soil. High rainfall, snow, and floods increase the loss of soil iodine due to melting of glaciers in hilly area due to global warming.
Pink or Himalayan salt is a kind of rock salt that is found in the foothills of the Himalayas in Pakistan region that also touches India. It is chemically similar to table salt as it also contains up to 98% of sodium chloride. Pink salt is also high in potassium, magnesium and calcium. Recently, its use has seen some rise in a large number of Indian households and almost 25% of the households in Jammu region use this crystalline salt, but in a study only 3.87% samples had adequate Iodine levels.
As it has been used by a lot of people in a way similar to what they had been using table salt, some researchers have found out that the Himalayan pink salt lacks iodine. Since, its use was widely prevalent in earlier centuries and the lack of iodine in it, very much indicates why the region where it was used widely was called as ‘Himalayan Goitre Belt’.
Let’s take a message to aware our self and others about the importance of iodine in maintaining normal health by consumption of iodine rich foods, adequate iodised salt, taking all precautions to check iodine losses while cooking or addition of salt after cooking to prevent Iodine Deficiency Disorders.
(The authors are Senior Associate Professor, Veterinary Medicine of SKUAST-Jammu.)