Adding a piece of fruit or a glass of milk to a teenager's breakfast may help protect them from depression, anxiety and disobedience, Australian research suggests.

A study of more than 800 students has found that a complex breakfast is directly linked to better mental health irrespective of family income, the student's weight or exercise routine.

Students who ate from more food groups for their morning meal scored higher on a child behaviour checklist, with an improvement in mood seen for every extra food type added.

"It didn't matter what they added, just that they added something different like a banana to their cereal to make that meal more complete with vitamins and minerals," said lead researcher Therese O'Sullivan, from the Telethon Institute for Child Health Research in Perth.

"From what we found, that makes a huge difference."

The team enlisted 14-year-old girls and boys and analysed their breakfast intake over three days.

They found that just one in four teens ate a high quality breakfast containing three or more of the five food groups, cereals, fruit, vegetables, dairy products, and meats and alternatives like beans, nuts and eggs.

"The overwhelming number just ate from two groups, and too many have just one or none at all, so there is much room for improvement," Ms O'Sullivan said.

The results were compared the students' behavioural scores in a complex questionnaire completed by their parents.

"For every additional food group added the mental health status improved markedly across the sample, and this was regardless of the family income, socio-economic status, the child's exercise (routine), weight and the rest of their diet."

She said this may be because mental functioning is affected by the absorption of a variety of nutrients.

Cereal and milk in particular supply calcium, iron and B vitamins that assist neurotransmitters, chemicals needed to transfer information in the nervous systems that are directly responsible for behaviour and mood.

Breakfast has long been thought vital but research has proven it is most important pre-adulthood as young people are not able to store nutrients as effectively.

"The liver stores nutrients, but kids have a much smaller liver, so until they become fully grown they can't store nutrients as effectively," the dietician said.

"For that reason breakfast is the most important way for them to get vitamins and minerals for brain function needed after the overnight fast."

The research will be presented at the national dieticians conference on the Gold Coast this week.

澳大利亚研究机构建议，给少年儿童的早餐加一块水果或者一杯牛奶有助于他们消除抑郁，紧张和违抗情绪。

对800多名学生的研究已经表明，复合早餐直接关系更好的心理健康，不必考虑家庭经济收入，学生体重和锻练常规。

吃更多食物品种早餐学生在儿童行为检查表上分数高一些，发现每添加一种食物就有心情改善。

“添加什么食物不重要，只要添加各种不同的食品，例如，把香蕉加到饭食中使得这一餐维他命和矿物质更完美，”珀斯, 佩思(澳大利亚城市)电视台儿童健康研究所的赛澳斯.奥莎丽娃主任这样说。

从我们的发现中看出，上述方法带来巨大变化。

研究组针对14岁的男孩和女孩，连续3天分析他们用的早餐。

研究人员发现只有四分之一的儿童吃高品质的含3种或者超过5种食物的早餐，这5种食物是谷物类，水果，蔬菜，奶制品和肉类，而豆，花生和鸡蛋为可替换食品。

奥莎丽娃说，“绝大部分儿童只吃2种类食物的早餐，更有许多只吃一种食物的早餐甚至不吃早餐。因此，大有改善空间。”

研究结果选来自一张由家长完成的学生行为特征详细调查表，对表上的记分进行分析比较得出结果。

每次添加食物各类，抽样试验儿童的心理健康状况明显改善。这个研究不顾及家庭经济收入，儿童锻练常规，体重和其它饮食。

她说，“这种改善可能是因为体内吸收了多种营养对心理机能起了作用。”

谷物和牛奶特别提供钙，铁和维他命B，其作用是辅助体内神经传递介质，它是一种化学物，在神经系统中传递信息所必需的物质，直接负责行为和情绪。

早餐一直被认为是必不可少的，而研究证明早餐对儿童来说极其重要，因为在成年以前，年轻人还不能够很有效地储藏营养。

营养学专家说，“肝脏储藏营养，但是儿童的肝脏非常细小，所以要到他们长大以后才能有效地储存营养。”

“正是这个原因，早餐是他们获取维他命和矿物质供应大脑之最重要途径，在一个长夜停食后大脑需要补充营养。”

本研究成果将在本周黄金海岸国民营养学专家会议上公布