HUNT 141 - Micronutrients (L22 - L32)

What are some functions of sodium in the body?

Regulates fluid balance, blood pressure, muscle contraction and active transport of glucose and amino acids.

What % of sodium is from salt added at the table?

10-15

Where does 75% of sodium intake come from?

Processed foods

What is the average intake of sodium in NZ?

2000 - 4000mg/day

How well is sodium absorbed?

Very well - 100%

What is a risk factor of consuming too much Na?

Hypertension, which increases risk of stroke and heart attack.

What factors impact hypertension?

Genes, age, weight, smoking, exercise, stress and diet.

What was in DASH diet 1?

High in fruits and vegetables, low fat dairy products.

What did the DASH diet find when sodium was lowered in terms of blood pressure?

Blood pressure went down.

What is the best way to measure sodium intake?

Urine sample, as 90% of sodium intake is excreted through urine.

What are some of the functions of potassium in the body?

Positive electrolyte, nerve transmission and muscle contraction

What foods are good sources of potassium?

Fruits and vegetables

What is the relationship between CVD risk and potassium intake?

As potassium intake increase, risk of CVD decreases.

Why do consuming ultra processed foods often lead to weight gain?

They don’t make you feel as full and people eat more than they need to.

How are food separated by how processed they are?

4 groups, all different levels of processing, called NOVA classifications

What are some risks of consuming too much ultra processed food?

Overconsumption, which increases the risk of developing NCD’s such as heart disease and obesity.

What is an effective way to increase dietary potassium and lower dietary sodium?

Switch table/cooking salt to a potassium chloride / sodium chloride mixed salt.

What is 99% of calcium used for in the body?

Bone/skeleton

What does low calcium intake cause?

Loss of bone mass, slows growth in children.

What % of calcium is absorbed from the diet?

25-30%

What can inhibit calcium from being absorbed?

Phytate, found in seeds and nuts and other charged minerals.

What are some promoters for calcium absorbtion?

Proteins, lactose and an acidic gut.

What happens to bones if not enough calcium is consumed?

Osteoporosis, bigger gaps in the trabecular bone which causes fragility.

What is peak bone mass?

The maximum amount of bone.

What determines someones peak bone mass?

Exercise, smoking, diet and medications.

What age do people reach peak bone mass?

20 - 30

Does NZ consume enough calcium?

Yes mostly

What three minerals is NZ soil low in?

Iodine, selenium and fluoride

What does iodine do in the body?

Maintains the body’s metabolic rate, integral part of the body’s thyroid hormones and is needed for growth and development.

What is the absorption of iodine?

100%

What are some symptoms of iodine deficiency?

Goitre, impaired motor and mental abilities and hypothyroidism.

Why was the intake of iodine so high in the 1980s in NZ?

Dairy industry used iodine as a disinfectant so it was in the milk.

Why have the rates of iodine consumption increased in recent years?

Due to the mandated fortification of salt and bread in NZ.

What was the pattern of iodine status from 1911 - 2011 in NZ?

Deficiency in 1930, Sufficiency in 1980s and deficiency in 1990-2000s

Why did iodine deficiency re-emerge?

Dairy industry iodine was discontinued, awareness was lower, people eating less salt and cooking at home was decreases.

What have cohort studies shown with lower iodine status in pregnancy and child development?

Less brain development.

Three ways to increase micronutrient intakes

Fortification, diverse diets and supplements

What food products in NZ are required to be fortified with iodine?

Salt and bread

What is inorganic selenium?

Selenium found in supplements or fertilizers and has low bioavailability.

What is organic selenium?

Selenium found in supplements or animal feed which has high bioavailability.

How well is selenium absorbed?

80%

What are some rich sources of selenium?

Fish, Organ meat and Brazil nuts.

What happens if someone is deficient in selenium?

They can develop Kashin-Beck disease which causes issues such as short stature and joint issues.

Why has NZ not implemented any health strategies to improve selenium deficiency?

We don’t have any Keshan’s disease or any other consequences reported.

Is the soil in NZ deficient in selenium and if so what can be used in bread to increase selenium in NZ diets?

Yes, we use australian grown wheat, as their soil has a higher concentration of selenium.

What is the main function of fluoride in the body?

Bones and teeth strength.

What is done to combat the deficiency of fluoride in NZ soil and water?

It is added to the drinking water.

What happens if you don’t get enough fluoride?

Increased risk of dental caries

What are some iron food sources?

Legumes, meat, fish, organ meats, weetbix and baby rice which are fortified.

Bioavailability

The proportion of intake of a nutrient that is absorbed and utilized.

Three things which influence bioavailability

Host related factors, chemical form (haem vs non-haem) and enhancers and inhibitors in a meal.

Absorption of haem Fe

25-30%

Absorption of non-haem Fe

5-15%

What are the main enhancers of iron absorption?

Vitamin C, haem iron paring and meat/fish factor.

What are the main inhibitors of iron absorption?

Phytate, Ca and Zn, caffeine and tannins.

What are some of the consequences of iron deficiency?

Decreased growth, decreases cognitive function, fatigue and spoon shaped nails.

Groups at risk of iron deficiency

Vegans, vegetarians, women, pregnant women, infants, blood donors and toddlers.

What is hereditary haemochromatosis?

A genetic condition where there is no control over iron excretion which results in iron build up in the joints, liver, heart and pancreas.

How is hereditary haemochromatosis treated?

Bleeding the patient so that the iron can bind to the new haemoglobin.

Zinc food sources

Dairy, legumes, meat, oysters and eggs.

What is an enhancer for zinc absorption?

Any animal protein

What is phytate?

It is a natural plant component needed for plants to germinate which inhibits the absorption of zinc and iron.

Function of iron in the body?

Helps red blood cells oxygen around the body.

Functions of zinc in the body?

Immune function, growth, vitamin A metabolism and reproduction.

Zinc deficiency results?

Growth stunted and little or no puberty, impaired immune competence.

Groups at risk of zinc deficiency

Infants, pregnant and lactating people, older people, vegans, low socioeconomic status and prolonged diarrhoea.

What causes zinc toxicity?

Too high consumption of zinc, usually from supplements, not food.