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Dietary Reference Intake (DRI) &
Recommended Dietary Allowance (RDA)


  1. What would be the correct way of discussing nutrient intakes in the US? Answer
  2. Do the amounts of the RDA change when you would like to slim down? Answer
  3. I don't really know if I am getting enough from what I eat. Is there any way to find out if I am taking in the RDA? Answer
  4. I've been working on a databse that I can use for myself that will allow me to track things like high blood pressure, blood sugar, mediations, exercise, meals and foods. Answer
  5. My professor said that the reason the RDA is doubled is because vitamin supplement manufactures lobbied to keep it high. Do you know if this is true? Answer
  6. Who is the RDA designed for? Answer


I am an American dietitian revising a United Kingdom nutrition book for the U.S. public. I was wondering what would be the correct way of discussing nutrient intakes for the general population (the book is designed for the general public). Should I talk about RDAs, USRDAs /RDI, or DRVs? What would be most appropriate?

The FNB (Food and Nutrition Board of the Institute of Medicine) updated RDAs (Recommended Dietary Allowances) from 2004 which are most familiar to the American public as you are probably aware. However, the NRC revisions will include Dietary Reference Intakes (DRI) covering estimated average requirements, recommended dietary allowances and maximum intake levels above which risk of adverse effects would increase.

As I understand the dietary reference intakes are the umbrella that covers all the other above requirements, allowances and intakes. If you have to go with something, go with dietary reference intakes (DRI). This ought to confuse a public who was just getting the hand of the RDAs after dealing with the USRDA (old food label term no longer used), MDR (old food label term no longer used), etc.


What is the RDA for fat, cholesterol, sodium, carbohydrates and proteins? Do these amounts change when you would like to slim down?

There is no RDA for fat, cholesterol, sodium or carbohydrate. The RDA for protein is age and gender dependent. Assuming you are an adult female older than 25 years, you would need 50 grams of protein per day.


I am familiar with the Recommended Dietary Allowance, but I don't really know if I am getting enough from what I eat. Is there any way to find out if I am actually taking in the RDA?

One way to know if you are getting the Recommended Dietary Allowance (RDA) for all the nutrients you need is to follow the Food Guide Pyramid. It provides from 1600 to over 2800 calories per day depending on which foods and the number of servings you eat. The assumption is made if you will choose a variety of foods from each of the 5 food groups (Grain, Vegetable, Fruit, Milk, Meat) then you will probably get 100% of your RDA.

But if you really want to know how much of each nutrient you are eating, I would suggest a thorough nutrient analysis. A registered dietitian could analyze your food intake from your records and report how your eating compares to the RDA with colorful charts and graphs. Their analysis will provide you with the nutrients that meet or fall short of your requirements based on your age and gender. Your personalized report could also include good food sources for the nutrients that are deficient in your diet. They could even analyze for all the fatty acids and amino acids in the food you eat.

Another alternative is to buy nutrition analysis software and do the analysis yourself and add in your supplements.


While looking at my weight, age and the certainty of increasing medical problems, I've been working on a database that I can use for myself that will allow me to track things like track high blood pressure, blood sugars, medications, exercise, meals and the specific foods.

While looking at the food section of the database, I decided finally to attack the USDA site and get the food information concerning the RDI requirements. Then start calculating from that information, what percentage of RDI I had reached with each meal and throughout the day. This is going well, as the information is available in the most general way concerning the calculations.

While searching I found two sites that seem to also provide something that is useful. One site: gives you a caloric intake to maintain a certain weight. I discovered that by just changing the weight in the information I would get a different caloric level that could be coupled with the USDA information to help round out some dietary tracking. Your site takes that much further which I was thrilled about.

You'll probably find me in your database, the 36-year-old, 314 pounds that was entered twice with this date. As I'm sure you're doing this for a paper or something like that. I did really enjoy the web site, very well done!

There are lots of really good, inexpensive software packages (< $60) out there that have huge databases (23,000 foods), including brand name foods not available in the USDA database. You may have had fun setting up yours and your time investment will probably add to your successful weight loss according to research. The off the shelf nutrition software packages have lots of whistles and bells and many issue updates with new databases and features. Some even track blood pressure, blood glucose and medications as well as diet and exercise. Find software that will track your weight, food intake and energy expenditure including exercise. You can still use your database (or spreadsheet) to track blood pressure, blood sugar or medications. Why not spend your energy on your healthy lifestyle by focusing on your daily food intake and exercise rather than designing and maintaining a database?

RDI is the Reference Daily Intake, which is the same as the old USRDA on the food label. Both are based on the 1968 Recommended Dietary Allowances. In other words, the new RDI recommends the same nutrient levels for all people regardless of age or gender and is used on new food labels as the Percent Daily Value i.e. everyone's DV for iron is 18 mg. Problem is, you don't need 18-mg iron because you are a male and in fact a high iron intake is not recommended for males. The RDA will tell you the specific amounts of nutrients based on your age and gender i.e. you need 10 mg of iron and adult women need 18 mg.

Any comparisons you make between your food intake and the RDI / Daily Values or RDA should be an average over at least 3 - 7 days. Individual meals vary in composition and variety and should not be evaluated out of the context of what you eat on the average.

BTW, I do not store people's data entered into the Healthy Body Calculator at this time and I am not doing a paper though one would be interesting research.

Thank you for your feedback on my site.


I am taking a nutrition course this semester and my professor mentioned that the RDA is doubled what is actually required for a few reasons, one being to ensure there are no deficiencies and the other because some vitamin supplement manufacturers lobbied to keep it high, so we will purchase their product.

Her second reason intrigued me. Do you know if this is true?

The RDA's are based on scientific research of both humans and animals and are set at levels to provide for 98% of all healthy people living in the US. There is a cushion built in so that if you get 67% of the RDA for a nutrient, you should be getting a minimum amount as an average person.

Remember that the RDA's are based on preventing deficiency symptoms specific to each vitamin and mineral. Some people think that the RDA values of some nutrients, specifically antioxidants, are set too low and recommend much higher levels.

I cannot comment on whether the vitamin supplement manufacturers lobby has been effective in keeping the RDA's high, but I doubt that this is true since the Food and Nutrition Board who meet to discuss changes every 5 years or so. These nutrition scientists base their recommendations on nutrition research.

The nutritional and health problems in the US today have less to do with preventing nutritional deficiencies and more to do with eating a healthy diet composed of real foods. Remember that the human body absorbs only about 10 - 15% of a vitamin pill and excretes the rest in urine and feces. Pretty expensive urine for some!


Who is the RDA's designed for? If a small adult ate enough to get all the nutrients in the RDA, he would be fat. If a very large adult ate exactly his RDA, he might be malnourished.

The Recommended Dietary Allowances (RDA) were established to cover the nutritional needs of all normal, healthy people living in the United States. Canada and some foreign countries each have their own RDAs. Canada has a Recommended Nutrient Intake (RNI).

The Food and Nutrition Board of National Academy of Sciences set the values for the RDA's based on human and animal research. They usually meet every five years to review current research on nutrients.

A Recommended Dietary Allowance is established for protein, vitamin A, D, E, K and B6, B12, C, thiamin, riboflavin, niacin, folacin, calcium, phosphorus, magnesium, iron, zinc, iodine and selenium. The recommended amount is set to cover 98% of all normal healthy people in the United States. It does not cover the nutritional needs of people with illness or chronic disease. There is a margin of safety built into the RDAs. The average, healthy person can consume at least 67% of their RDA and still be adequately nourished.

The RDA for protein is the only nutrient containing calories. Protein, fat, carbohydrate and alcohol contribute calories. Vitamins and minerals do not contain calories. All foods except table sugar contribute nutrients to your diet. Depending on which foods you choose, the calorie content of a diet that would fulfill an individual's RDA could range from 1600 to 2200 calories. A small adult would not necessarily get fat, nor would the large adult be malnourished. Overweightor underweight is the result of eating more calories or fewer calories respectively, than a person needs. It is the food choices that a person makes in addition to exercise that determines body weight.






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