Why have UK selenium intakes fallen in recent decades?

The UK once imported much of its bread-making wheat from North America, where soils are rich in selenium. More of the wheat now comes from the UK and Europe, where soils contain less.

What are the effects of selenium deficiency?

Selenium deficiency reduces antioxidant protection and weakens the immune system. Severe deficiency in low-selenium areas of China causes Keshan disease, which damages the heart muscle.

What are the effects of excess selenium?

Excess selenium causes selenosis, with brittle hair and nails that may fall out. Garlic-smelling breath, skin rashes and nerve damage can also occur.

CCEA A-Level Nutrition and Food Science 3310

Protein

Topic overview Functions of protein Amino acids, biological value and complementation Animal and plant sources of protein Novel protein sources Nitrogen balance and protein requirements

Fat

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Alcohol

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Food SustainabilityOption A

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Food WasteOption A

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Changing Consumer BehaviourOption A

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Food Safety Through the Food ChainOption B

Topic overview WHO and shared responsibility for food safety Animal and plant health risks The Food Standards Agency and DAERA GMP, quality assurance standards and traceability HACCP in food-serving establishments Hygiene ratings, food law inspections and EHPs

Microbiological ContaminationOption B

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Food AdditivesOption B

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Food AllergensOption B

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Research Skills

Topic overview Primary and secondary research Questionnaires and interviews Food diaries, observation and sensory evaluation Sampling and research ethics Evaluating and referencing sources Analysing and presenting data

Minerals

Selenium and zinc

3 things to know
AS 1

Overview

Selenium's antioxidant role and falling UK intakes, Brazil nuts, and zinc's roles in growth, immunity and healing, its sources, deficiency, excess and higher needs in men.

What you need to know

Answer each one before you reveal it.

Your recallNot started

Key term

What are the functions of selenium?

Key term

Name valuable food sources of selenium.

Key term

Why does the selenium content of cereals and vegetables vary so much between countries?

Questions from this subtopic

Each one with the model answer underneath.

1
What are the functions of selenium?
Model answer
Selenium is part of the enzyme glutathione peroxidase, which protects cells from damage by free radicals. Selenium is also needed to make active thyroid hormone and for a healthy immune system and sperm production.
2
Name valuable food sources of selenium.
Model answer
Brazil nuts are an exceptionally rich source of selenium. Fish, shellfish, meat, offal and eggs are also good sources.
3
Why does the selenium content of cereals and vegetables vary so much between countries?
Model answer
Plants take up selenium from the soil, and soil selenium differs widely between regions. Soils in the UK and much of Europe are relatively low in selenium.
4
Why have UK selenium intakes fallen in recent decades?
Model answer
The UK once imported much of its bread-making wheat from North America, where soils are rich in selenium. More of the wheat now comes from the UK and Europe, where soils contain less.
5
What are the effects of selenium deficiency?
Model answer
Selenium deficiency reduces antioxidant protection and weakens the immune system. Severe deficiency in low-selenium areas of China causes Keshan disease, which damages the heart muscle.
6
What are the effects of excess selenium?
Model answer
Excess selenium causes selenosis, with brittle hair and nails that may fall out. Garlic-smelling breath, skin rashes and nerve damage can also occur.

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