Reason Why Nutritional Guideline Is Complicated
- Kota Shimada
- Mar 8, 2020
- 5 min read
Updated: Nov 12, 2021
As we concern ourselves in health improvement, one of the key factors that revolve around this topic is nutrition. However, it is somewhat confusing because information tends to change frequently and difficult to figure out what we should be following. The questions I want to address in this article is "why there is so much complication and ambiguity in nutritional guideline?".
From Sugar Does Not Cause Diabetes to Limiting Sugar
Let's compare Dietary Guideline for Americans from 1980 to 2018.
Despite the trend of diabetes been increasing (about 5.53 million) in 1980 Dietary Guideline concluded that over consumption of sugar does not lead to diabetes where population was already consuming about 130 lb. of sugar per year per person. They've also stated that there is no evidence that sugar caused heart attack or blood vessel disorder.
Now in 2018 they are advising the population to not consume more than 10% of calorie consumption from sugar. In other words, if you are following 2000 calorie diet, you are allowed to consume 200 calories or 50 g of sugar per day or 40 lb per year.
Huge step to better health but took more than 20 years to get here with 23.35 million people as of 2015 are being diabetic. Most likely this number will keep on rising.
Why did it took this long and why are information still unclear? To understand this, we need to go through research history of salt and sugar.
Two White Crystal
When looking back in history, like back before we were evolved, four-limbed creature, tetrapod learn to live between sea and land by adapting their kidney to be able to filter and retain sodium.
After tetrapod evolving to amphibians, reptiles, and mammals, we have consumed food sources that were rich in sodium mainly from marine prey. Obviously, there were no dietary guideline so they were relying mainly on their senses, which we also have called homeostasis. So if you think about it, their kidney must have capacity to excrete huge amount of salt. In fact, research has shown that with normal blood pressure and kidney function, we can easily excrete 10 times as much salt as we consume on regular basis.
When you look into history, almost every major Roman city was located close to some sources of salt. According to Salt: World History by Mark Kurlansky, Roman has consumed average of 25 grams of salt per day!
In sixteenth century Europeans were estimated to consume around 40 grams of salt per day and increased to 70 grams per day in eighteenth century.
Salt Causing Hypertension Myth
Although there were no blood pressure assessing tool in 1800s, however, we do know that case of hypertension in the US was 5-10 percent in 1900s. In 1939 hypertension in adults was 11-13 percent. However, hypertension gradually increased at in 1975, 25 percent and in 2004, 31 percent of population was monitored as hypertension.
If salt was main cause of hypertension and heart disease, shouldn't we have hundred cases, if not thousands, in Europe for consuming well over 40 grams per day?
High salt intake was there for centuries, not just to flavor the food but also to preserve them. Yet when you look at Dietary Guideline it is still suggesting us to limit our sodium intake to 2300 milligram (2.3g). The question comes why?
Salt was viewed as caused of high blood pressure in 1920s by a medical doctor in New York. Him and his coworkers published papers to advise medical professionals that restricting salt has potential of lowering blood pressure. He also hypothesized that consumption of salt was irritating the kidney to cause overwork. However, there was enough publication to oppose with this theory.
Rice Diet and Salt Sensitive Rat
Then a doctor by the name Walter Kempner invented a diet called Rice Diet in 1939. Diet is low in salt and mainly consumed with rice and fruits. No meat of course, but also no nuts canned or dried fruits were allowed. No vegetable juice but was allowed to add more sugar. Talk about carb loading right?
Kempner's theory was salt is waste product of the kidney and reducing salt can relieve kidney from overwork. Kempner reported that Rice Diet has been successfully used for people with hypertension, kidney disease, and even diabetes. Case reports have pull the attention of you know who, media. Was the diet successful? Blood pressure did drop on some of his patients but majority of his patients were excessively high in blood pressure and one study showed there were 83% of patients showed no effectiveness in Rice Diet. However, Kempner reported his diet to be 64% successful.
Regardless of the fact, Rice Diet was recognized as successful diet and low-salt was effective in treating hypertension.
Then in 1950's Dr. Lewis Dahl proven the high salt consumption lead to hypertension by using what we now know as "Salt-sensitive rat". That's right. He used salt-sensitive rat and gave salt and showed that the blood pressure of rat has elevated.
Sugar Is Harmless
Interesting thing is until 2002, thought of obesity can elevate blood pressure and cause hypertension was not popular theory. However, sugar consumption in 1700 in England was 4 lb per person per year. In 1950, that number skyrocketed to 100 lb per year. In the US, this number was reached by 1920. Yes the same time the salt was thought as a cause of hypertension.
In 1950's American scientist promoted the idea that dietary fat was cause of heart disease but England researcher, at the same time, thought that sugar was to be blamed. Yet in 1960's American Heart Association claimed saturated fat was cause of heart failure and advised all Americans to reduce intake of animal fat and increase their intake of vegetable oil.
Sugar industry also played role in sugar is harmless concept by sponsoring popular events like Olympics to provide positive image of sugar. Even in 1977, obesity was caused by inactivity. This is where true mis-direction started from "harm calorie" to "total calorie", which majority of current fitness industry still follow today.
From 1975, there has been number of studies that were published and funded by sugar industry.
What is Happening Now?
Little by little true science and common sense has started to marge into our understanding of nutrition. However, there still is information that are closed to the public because of possible pressure from outside sources. And with current power and speed of media, information is carried on without proper understanding of the truth which creating major confusion.
Many of the information you may currently have and hearing from health professionals including fitness professionals, nutritionist, dietitian, and so on may be biased and manipulated in improper manner. However, most likely it is not their fault for educational materials they have learned from may have been already biased.
However, keep in mind that for nutrition, there is no one right answer. Depending on your current condition, you may need to be following completely different nutritional guideline then suggested.
What I suggest first is to get your facts about basic nutrition and physiology straight. If anybody is talking about nutrition without conversing about how body works, they are most likely reciting what they have read on text book or from their certification courses.
It is a tough topic, however, I hope that I have made you curious and start doubting the information you currently have. Trust me, it took me a while to give in to the mindset that I was taught wrong.
Happy Learning,
Kota Shimada
Reference:
Comments