Nowadays, more than 50% of people gobble down some kind of pills regularly. Most of the pills are nutrients such as multivitamins and fibers. Recent research has unfortunately disappointed us by suggesting that all these essential nutrients in pills might behave differently in our bodies from those in foods. Nutrient pills are either less effective to prevent heart diseases or cancers, or not protective at all. Instead, some may harm our health. Even well informed people are baffled by the confusing sometimes contradicting scientific reports. The science of nutrition and health is becoming some kind of pseudoscience.

For example, at the beginning, we were told that vitamin E supplement could protect our hearts and prevent cancers. The mechanism sounds straightforward. Vitamin E, or tocopherol, is a strong antioxidant which can reduce the oxidation in cells to prevent cell damages. It has been shown in vitro, and somewhat confirmed in vivo (for example, in mice and in rabbits). Observational studies such as the Nurse Health Study suggested that those who took vitamin E pills or ate foods rich in vitamin E had significant low incidences of heart diseases. It might be THE magic stuff we are searching for.

Follow up clinical trials didn’t support this optimistic view. The Health Outcome Prevention Evaluation Study (HOPE) quite clearly denounced the claimed vitamin E effects. A recent meta-analysis reported a similar negative finding for the mega-dose (400 IU above) vitamin E supplements. The Women Health Initiative Study(WHI) suggested that vitamin E supplements wouldn’t prevent cancers either.

Beta-carotene has suffered a similar fate. Previous observational studies suggested that beta-carotene could prevent heart diseases and cancers. Again this makes sense. Beta-carotene, or carotenoid in general, is also an antioxidant and abundant in vegetables and fruits. People who eat lots of vegetables and fruits are healthier than those who don’t. However, no clinical trials (randomized or not) supported the original findings. Even worse, the Carotene and Retinol Efficiency Trial (CARET) found that beta-carotene supplements among smokers (who generally have higher oxidation than nonsmokers) actually caused a higher lung cancer incidence. This is completely counterintuitive.

Nonetheless, there must be some easy and inexpensive ways to prolong our lives. Some people are still stuck in antioxidants and are trying new ones such as lycopene and flavonoids, but others are willing to accept new ideas.

Nutritionists start to revisit the idea of dietary pattern or food matrix. Using factor analysis, people have identified several dietary patterns. The purpose of these studies are to produce some consistent dietary patterns which are healthy in hearts or preventive against cancers. So far, nothing is earthshaking. The best dietary pattern is always vegetables and fruits. People know this for years.

Some clinical trials (feeding studies) also studied the effects of vegetables and fruits on variety things such as high blood pressure (Dietary Approaches to Stop Hypertension, DASH), and insulin level. The results are encouraging at least.

Although all these scientific endeavors are admirable, they are based on different philosophies. Modern science is based on reductionism– dissecting everything into component. If vegetables are good for our health, there must be some chemicals responsible for it. It is how we discovered so many essential nutrients.

The food pattern studies are based on old fashioned holism. All nutrients interact with each other in our bodies. The physiology of digestion, absorption, energy utilization, and protein synthesis are so complex that you need a right combination of nutrients to do the work. But how they interact is difficult to understand.

Ancient people, without much knowledge about biochemistry and nutrition, relied on holism. For instance, they knew that meats were more nutritious than vegetables, which is true because meats have more proteins and fats, i.e., higher energy density. In fact, our human bodies are built on craving energy dense foods: high protein, high fat, and high sugar. Therefore, McDonald’s fatty sandwiches are not the culprit for our weight increase. Instead, it is our bodies that push us to eat meats.

Nevertheless, a healthy diet is a balanced diet. It must contain enough meats or dairy products for proteins and vegetables and fruits as the primary nutrient source. The rationales include: a) vegetables and fruits have almost all vitamins and minerals; b) meats and dairy products are more efficient to provide proteins. However, there are many illusions about balanced diet.

One common view is that because primitive human beings mostly ate vegetables and fruits, modern human beings should eat more vegetables and fruits too. This is an inaccurate statement. Yes, our human bodies are built in the context of plant foods not around animal products. Thus we need to eat plant foods to provide essential vitamins and minerals. However, this is largely due to the side-effect of plant eating. Animal products can provide almost all essential vitamins and minerals. In addition, our bodies are designed to efficiently use and store energy to sustain us in the constant presence of hunger. Since meats and dairies are rich in nutrients with high energy density, in a sense, our bodies prefer animal products to plant foods. Therefore, there is nothing wrong eating meats or drinking milks. In fact, it is the overconsumption that kills people. You eat more vegetables to avoid overconsumption, not to mimic the primitive life. If you can control yourself by limiting energy intake, you don’t have to abstain from meats.

Here is another nonsense. Recently, dairy companies are persuading people to drink more milk, especially the low fat milk or skim milk because studies have shown that drinking a lot of milk can maintain your weight if not lose your weight, and prevent heart diseases. It is true that milk is one of the best nutrient balanced foods (the other one is eggs) except for low in iron. However, milk, and all dairy products are higher in proteins, sugar, and fats. Even those low fat cheeses have much high fat contents than vegetables and fruits do. Drinking three glasses of milk a day means having more energy intake than before. People may think they can reduce the food intakes after drinking a glass of milk. Unfortunately, it is not true. Those who continuously gain weight are those cannot control their desire to eat. They tend to eat till the plate is clean, not till they feel satiated. Furthermore, if drinking milk won’t reduce intakes of other meats, the diet is totally unbalanced.

Although knowledgeable people start blaming their genes for their unstoppable weight gain, we can safely say that it is the dietary habit that causes their obesity. If people can stop pulling a second plate of foods during dinners, they are surely heading toward healthy lives.