Your Brain on Food If you sucked all of the moisture out of your brain and broke it down to its constituent nutritional content, what would it look like? Most of the weight of your dehydrated brain would come from fats, also known as lipids. In the remaining brain matter, you would find proteins and amino acids, traces of micronutrients, and glucose. The brain is, of course, more than just the sum of its nutritional parts, but each component does have a distinct impact on functioning, development, mood, and energy. So that post-lunch apathy, or late-night alertness you might be feeling, well, that could simply be the effects of food on your brain. Of the fats in your brain, the superstars are omegas 3 and 6. These essential fatty acids, which have been linked to preventing degenerative brain conditions, must come from our diets. So eating omega-rich foods, like nuts, seeds, and fatty fish, is crucial to the creation and maintenance of cell membranes. And while omegas are good fats for your brain, long-term consumption of other fats, like trans and saturated fats, may compromise brain health. Meanwhile, proteins and amino acids, the building block nutrients of growth and development, manipulate how we feel and behave. Amino acids contain the precursors to neurotransmitters, the chemical messengers that carry signals between neurons, affecting things like mood, sleep, attentiveness, and weight. They're one of the reasons we might feel calm after eating a large plate of pasta, or more alert after a protein-rich meal. The complex combinations of compounds in food can stimulate brain cells to release mood-altering norepinephrine, dopamine, and serotonin. But getting to your brain cells is tricky, and amino acids have to compete for limited access. A diet with a range of foods helps maintain a balanced combination of brain messengers, and keeps your mood from getting skewed in one direction or the other. Like the other organs in our bodies, our brains also benefit from a steady supply of micronutrients. Antioxidants in fruits and vegetables strengthen the brain to fight off free radicals that destroy brain cells, enabling your brain to work well for a longer period of time. And without powerful micronutrients, like the vitamins B6, B12, and folic acid, our brains would be susceptible to brain disease and mental decline. Trace amounts of the minerals iron, copper, zinc, and sodium are also fundamental to brain health and early cognitive development. In order for the brain to efficiently transform and synthesize these valuable nutrients, it needs fuel, and lots of it. While the human brain only makes up about 2% of our body weight, it uses up to 20% of our energy resources. Most of this energy comes from carbohydrates that our body digests into glucose, or blood sugar. The frontal lobes are so sensitive to drops in glucose, in fact, that a change in mental function is one of the primary signals of nutrient deficiency. Assuming that we are getting glucose regularly, how does the specific type of carbohydrates we eat affect our brains? Carbs come in three forms: starch, sugar, and fiber. While on most nutrition labels, they are all lumped into one total carb count, the ratio of the sugar and fiber subgroups to the whole amount affect how the body and brain respond. A high glycemic food, like white bread, causes a rapid release of glucose into the blood, and then comes the dip. Blood sugar shoots down, and with it, our attention span and mood. On the other hand, oats, grains, and legumes have slower glucose release, enabling a steadier level of attentiveness. For sustained brain power, opting for a varied diet of nutrient-rich foods is critical. When it comes to what you bite, chew, and swallow, your choices have a direct and long-lasting effect on the most powerful organ in your body.
大腦對食物的反應 假如將腦的全部水份抽乾 並將它分解為其所組成的營養成分 它會是什麼樣子呢? 脫水後的腦 其多數的重量來自脂肪 亦稱為脂質 其餘的大腦物質, 你會發現有蛋白質和胺基酸、 少許的微量營養素 和葡萄糖 當然,腦並非只是它營養成分的總和 然而每種成分對其運作、發育、 情緒和活力確實有獨特的影響 所以你午餐後可能感覺遲鈍 或深夜感覺機敏 那可能只是食物對大腦的影響 腦中的脂肪, ω−3 與 ω−6 脂肪酸極為重要 這些和預防退化性腦病變有關 的必需脂肪酸 必須來自我們的飲食 所以吃富含 ω 脂肪酸的食物 如堅果、種子和富含脂肪的魚 對於細胞膜的製造和維持極其重要 ω 脂肪酸是有益大腦的脂肪 但長期食用其他脂肪 ─ 如反式和飽和脂肪 ─ 可能會危害腦部的健康 同時,蛋白質和胺基酸 是生長和發育的基本營養素 影響我們的感覺和行為 胺基酸含有神經傳導物質的前體 神經傳導物質 是神經元之間攜帶信號的化學信差 會影響一些狀況,例如情緒、 睡眠、注意力及體重 這些是下列的原因之一: 吃一大盤意大利麵後有寧靜感覺 或一頓富含蛋白質的餐後更機靈 食物中化合物的複雜組合 能刺激腦細胞釋放 改變情緒的去甲腎上腺素、 多巴胺和血清素 但胺基酸不容易到達腦細胞, 而且必須競爭有限的機會 含各種食物的飲食 可幫助維持大腦信差的均衡組合 而且讓你的情緒 不會過度偏向一邊或另一邊 如同身體的其他器官 大腦也會因 微量營養素的穩定供應而受益 水果和蔬菜中的抗氧化物質 強化大腦對抗破壞腦細胞的自由基 讓腦部得以長時間運作良好 若沒有效用大的微量營養素 ── 例如維生素 B6、B12 以及葉酸 大腦將容易罹患腦疾病和智力衰退 微量的礦物質 ─ 鐵、銅、鋅及鈉 對腦部健康和早期認知發育也很重要 為使大腦有效地轉化及合成 這些寶貴的營養素 它需要燃料,而且很多 人類大腦只佔體重的 2% 但耗費高達 20% 的能源 大多數的能源來自碳水化合物 身體會將它消化成葡萄糖, 也就是血糖 事實上, 大腦額葉對於葡萄糖降低非常敏感 心智機能的改變 是營養素缺乏的主要徵候之一 假設我們規律地攝取葡萄糖 那麼食入特定的碳水化合物 是如何影響大腦呢? 碳水化合物有三種型式: 澱粉、糖及纖維 然而在多數的營養標籤上 它們被集中計為「總碳水化合物」 糖和纖維亞群對總量的比例 影響身體和腦如何反應 高糖食物 ─ 如白麵包 可導致葡萄糖快速釋入血液 然後迅速下滑 隨著血糖快速下降, 我們的專注時間和情緒也減退 反之,燕麥、穀物 和豆類的葡萄糖釋出較慢 使得專注力較穩定 為讓腦力持久 選擇營養豐富的多樣化飲食極為重要 當涉及你所咬、咀嚼、吞嚥的食物時 你的選擇對體內最強有力的器官 -- 腦, 將有直接且長遠的影響