B.5 Vitamins
Written specifically for students to provide help and support for the IB Diploma chemistry programme this page provides full coverage of the syllabus content of Option B - sub topic B.5. It encourages you to think critically and provides many questions with full worked answers so that you can monitor and improve your knowledge and understanding.
Learning outcomes
After studying this topic you should be able to:
Understand:
- Vitamins are organic micronutrients which must be obtained from suitable food sources, as (mostly) they cannot be synthesized by the body.
- The structure of a vitamin can be used to predict whether the vitamin is soluble in water or fat.
- Most vitamins are sensitive to heat.
- Particular diseases caused by a lack of specific vitamins in the diet affect millions of people worldwide.
- Compare the structures of vitamins A, C and D.
- Discuss the causes and effects of vitamin deficiencies in different countries and suggest possible solutions.
Relationships & vocabulary
Nature of science
The explanation of deficiency diseases (e.g. scurvy and beriberi) in terms of lack of specific vitamins (vital amines) was due to scientists seeking a cause for specific observations.
International-mindedness
The sale of vitamin pills (and the food supplements industry in general) has become a very lucrative business in many countries.
There is an increase in Vitamin D deficiency, partly because humans protect their skin more from sunlight.
Vocabulary
micronutrient
| micronutrient | vitamin A (retinol) | vitamin D (calciferol) | vitamin C (ascorbic acid) |
| rickets | xerophthalmia | osteoporosis | scurvy |
Learning slides
You can use this slide gallery for learning or for reviewing concepts and information. It covers all the key points in the syllabus for this sub-topic.
Something to think about
In the 1970s Frank Rowland and Mario Molina predicted that CFCs would interfere with the ozone layer. Their work was treated with scepticism, but in 1985 satellite evidence showed that the depletion of ozone above the Antarctic was in fact much greater than had been predicted. This coincided with a rise in the number of cases of skin cancer in countries like Australia and New Zealand due to the increasing amounts of ultraviolet radiation reaching the surface of the Earth. In order to protect their skin from exposure Australians stated to apply sunblock whenever they were out in the sun. However by trying to avoid one health problem they have inadvertently brought about a serious vitamin deficiency problem. Very few foods contain vitamin D and the body normally obtains its vitamin D through the action of the ultraviolet light from the sun with cholesterol in the skin. A lack of vitamin D leads to rickets and osteoporosis.
Even though it is now mandatory in Australia to fortify edible oils and spreads with vitamin D, it has been reported in 2014 that 25% of all Australians are suffering from vitamin D deficiency. In order to counterbalance this lack of vitamin D, many Australians have taken to buying vitamin D supplements (or multi-vitamin supplements which contain vitamin D) and it is reported that the sale of such supplements increased three-fold during the decade 2001 to 2010.
Trying to balance the negative effects of too much sunlight with the negative effects of too little sunlight is no easy task.
Test your understanding of this topic
(Note that your teacher may have restricted your access to some or all of these questions and worked answers if they are going to use them as a class test or set them as an assignment.)
For ten 'quiz' questions (for quick testing of knowledge and understanding with the answers explained) see MC test: Vitamins.
For short-answer questions see Vitamins questions together with the worked answers on a separate page Vitamins answers.
More resources
Unfortunately vitamins are big business so a search of 'vitamins' on the web and YouTube produces much that is useless from a scientific viewpoint.
1. A couple of reasonable sites for some information on vitamins are one from a sports coach and one from netdoctor.
2. The benefits of vitamin D and the problems of vitamin D deficiency.