What are the nutrients in fish that make it a brain food?

Docosahexanoic acid (DHA), an omega-3 fatty acid, is one of the components of brain tissue. DHA may influence neurotransmitters in the brain, helping brain cells to communicate better with each other. The brain is made up of more than 50% fat, 25-35% of which is made up of the essential fatty acid DHA.

“DHA-rich food sources include human milk, cold water fatty fishes such as salmon, tuna, sardines and mackerel. Other sources include seafood like oysters and shrimps,” says the Department of Nutrition and Dietetics at KK Women’s and Children’s Hospital, a member of the SingHealth group.

Methylmercury in fish: points to note

In recent years, there have been concerns about the levels of methylmercury in fish, especially the effect on foetal development, infants and children.

Methylmercury exposure can adversely affect a baby's growing brain and nervous system, leading to effects on the child’s:

  1. cognitive thinking,
  2. memory,
  3. attention span,
  4. language skills,
  5. fine motor skills and
  6. visual spatial skills.

Hence, the US Food and Drug Administration (FDA) recommends to have 1 to 2 serves of fish a week, from the age of 2 years (1 serve = 2 ounces for children 4 to 7 years, or 4 ounces for older children).

In addition, the US FDA also recommends that infants, young children and pregnant women avoid the following fishes with high mercury levels:

  • Swordfish
  • King mackerel
  • Spanish mackerel (Batang), which can be consumed safely when limited to 1 serve a week.
  • Shark
  • Tilefish
  • Big eye tuna
    • ​Other varieties of tuna are lower in mercury.
    • ​​1 serving of yellow fin and albacore (or white) tuna can be consumed once a week, and canned light tuna (including skipjack) can be consumed 2 to 3 times a week.
    • If you are uncertain of the type of tuna in your canned tuna, limit to one serving a week.

Is there any special cooking method to retain the nutrients in fish?

Omega-3 fatty acids are relatively stable in whole foods. However, deep-frying the fish may destroy the Omega-3 fats significantly. Baking, broiling and steaming causes minimal Omega-3 fat losses. 

For overall good health (both for obesity prevention and for heart health), it is encouraged that foods be prepared using healthy cooking methods such as

  1. boiling,
  2. steaming,
  3. pan-frying
  4. baking and
  5. grilling.

It is also important to cook using mono-unsaturated or polyunsaturated oils, e.g. olive, canola, sunflower, soybean, peanut and rice bran.

Other sources of Omega-3

If your child does not eat fish or is vegetarian, he can obtain plant sources of omega-3 fatty acids, known as alpha-linolenic acid, mainly from canola oil, soybean oil, linseeds (flaxseeds) and walnuts.

If you decide to use a supplement, be mindful of the following:

  1. Choose a supplement that is appropriate for your child’s age. Always check the instructions on the package and do not exceed the suggested dosage.

  2. Avoid giving capsules for children under 3 years of age as they are a choking hazard. Omega-3 supplements now come in gummies or liquid form.

  3. Purchase supplements made from refined oils from the flesh of fish instead of fish livers. Cod liver oils, commonly consumed by many toddlers in Singapore, contain fish oil, vitamin D and pre-formed vitamin A (retinol). Pre-formed Vitamin A (retinol) is fat-soluble and excessive intake can lead to dizziness, nausea, headaches, coma and even death. Different br​ands contain varying amounts of Vitamin A. The Singapore Recommended Dietary Allowance​ (RDA) is 250 mcg for children aged 1 to 2 years, 300 mcg for 3 to 6 years, 400 mcg for 7 to 10 years and 575 mcg for 10 to 12 years.

  4. If your child is vegetarian, you can consider offering an omega-3 supplement made from microalgae oils.

How does a healthy diet during a child’s early years assist in his brain development? Why?

A healthy balanced diet comprising foods from all major food groups is essential for optimal growth which in turn aids the child’s intellectual growth. This is because the early years of life are characterised by rapid growth and development.

“A well-nourished child will have the energy to respond to and learn from the stimuli in their environment,” says our experts.

What other essential nutrients contribute to the brain development of a child from toddler to preschooler age?

Iron is another nutrient important for brain development and cognitive performance. Iron in foods is found in two forms, heme and non-heme iron.

Sources of heme-rich iron are generally of animal origin such as meat, poultry and fish. Heme iron is more easily absorbed by the body.

Non-heme iron food sources include

  1. grains
  2. ​vegetables
  3. dried fruits such as raisins and apricots
  4. iron-fortified products such as cereals and breads.

A 1-2 year old child needs ½ a serving (45g) of meat and alternatives a day, while a 3-6 year old child requires 1 serving (90g) of meat and alternatives a day.

To help increase non-heme iron absorption, vitamin-C rich foods like fresh fruit and lightly-cooked vegetables are also encouraged with meals.

Choline has been shown to play a significant role in the fetal and infant brain development, affecting the parts of the brain that are involved in memory and life-long learning abilities.

Choline like DHA, is also found in human milk. Other food sources of choline include meat, poultry, fish, egg yolk and wheat germ.

What about antioxidants – what role do they play in aiding brain development? What are the sources of antioxidants?

Fruits and vegetables are good sources of antioxidant vitamins, which protect the brain from oxidative damage by free radicals.

Different fruits and vegetables contain varying amounts of micronutrients, so it is important to consume a variety! As some antioxidant vitamins like vitamin C are water-soluble and destroyed by heat, cut your vegetables after (not before) washing, and cook them lightly.


A common question in many parent's mind is, "Are there foods that are good for my child’s brain development?"

Our dieticians share foods that are good for the brain, and suggests preparation methods that will not destroy the brain-boosting nutrients in these foods.

Top 10 foods for a child's brain development

 

Food

Why is it good?

Preparation​ method

1

Salmon

Rich in Omega-3 fatty acids, specifically Docosahexanoic Acid (DHA), which is essential for brain growth and function.

Omega-3 fatty acids are relatively stable in whole foods.

However, deep-frying the fish may destroy the Omega-3 fats significantly. Baking, broiling and steaming causes minimal Omega-3 fat losses.


2

Eggs

Egg yolks are an important source of Choline, which is important for brain and memory function.

Choline is sensitive to water and may be destroyed by cooking and food processing. Young children are advised to consume fully cooked eggs to prevent the risk of food poisoning.
Eggs Brain Food

3

Lean meat

Lean meats are rich sources of minerals like zinc and iron. 

Low zinc levels has been shown to lead to faulty memory as zinc plays a role in the communition of nerves channels within the brain. Iron aids in supplying oxygen to the brain, and iron deficiency is associated with cognitive and attentional deficit.

There is no appreciable loss of minerals during the cooking of meat. You can consider a range of cooking methods including stir-frying, baking, roasting, and braising. 


4

Dairy

Milk, cheese and yogurt are rich sources of calcium. Besides its role in bone health, calcium forms an important part of the electrical signaling system within the brain.

Calcium is generally unaffected by cooking.

5

Nuts and seeds

Packed with protein and essential fatty acids, nuts and seeds are also high in vitamin E, B group vitamins, iron and zinc, which have been shown to be important for brain function.

Nuts and seeds are naturally high in beneficial monounsaturated fats, however intake should be limited if there are weight concerns. Walnuts and flaxseeds, in particular, are rich in Omega-3 fats.

Cooking does not affect the nutritional quality of nuts and seeds. However, roasted nuts or seeds may have added fat, salt and/or sugar.

6

Wholegrains, including Oats

Wholegrain foods are rich in carbohydrates and fibre, hence helping to maintain a constant supply of glucose for brain energy and function.

They are also high in B group vitamins. The combination of nutrients in wholegrain foods have been shown to improve auditory attention and memory cognition.

Carbohydrates and fibre are not affected by cooking. However, some B vitamins like folate are water-soluble and are easily destroyed by heat.

7

Beans

Beans are a good source of carbohydrates, fibre and B vitamins.

As above wholegrains.

8

Colourful and dark green vegetables, especially broccoli

Fruits and vegetables, especially those with coloured pigments are rich in antioxidants.

Antioxidants protect the body and the brain against oxidative stress and free radical damage.

Antioxidant losses are greatest when vegetables and fruits are cooked in water. It has been shown that boiling and pressure cooking leads to high losses of nutrients, whereas microwaving, baking and grilling leads to lower losses.​ 

Stir-frying, as it uses little water and oil and is over high heat for a short period of time, should also lead to low losses.

9

Colourful fruits especially blueberries, strawberries, red/purple grapes

10

Water

Although not a food nor containing any nutrients, water is important for hydration, which helps to maintain blood flow and oxygen transport to all parts of the body.

Dehydration can cause lethargy, irritability and reduced ability to stay alert and concentrate.

As is, no preparation needed.

Is essence of chicken essential for children?

A few studies have shown that essence of chicken may improve mental focus and reduce stress. However these studies are generally performed in small numbers and may be biased as they are conducted by the product company.

Hence the benefits of essence of chicken for a child’s IQ and brain development is inconclusive, and it is an area that requires more unbiased research conducted on a larger group.

Ref: O24​

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