What is the Chronic Disease Risk Reduction (CDRR)?
The Chronic Disease Risk Reduction (CDRR) is a reference intake value established by the National Academy of Medicine as part of the Dietary Reference Intakes (DRIs). It signifies the level of nutrient intake above which a reduction is expected to lower the risk of developing a chronic disease in an apparently healthy population. The CDRR is based on extensive evidence that shows a causal relationship and an intake-response relationship between the nutrient and the chronic disease risk. To date, only one nutrient has met this strict scientific criteria.
The Purpose of the CDRR
For decades, nutrient guidelines focused primarily on preventing deficiency and, through the Tolerable Upper Intake Level (UL), preventing toxicity from excessive intake. The CDRR was introduced to address the middle ground: excessive intakes that don't cause immediate toxic effects but do increase the risk for long-term chronic conditions, especially for a population where average intake is already high. This shift reflects a move toward considering diet not just for basic nutrition but also for its role in preventing major public health burdens like cardiovascular disease.
The Distinction Between CDRR and UL
The CDRR should not be confused with the Tolerable Upper Intake Level (UL). As defined by the National Academies, the UL is the highest daily intake level likely to pose no toxicological risk of adverse health effects. For example, the UL for some vitamins exists to prevent liver damage from extremely high doses. In contrast, the CDRR is set at the lowest intake level at which there is sufficient evidence of chronic disease risk reduction. For a nutrient with a CDRR, like sodium, a UL is not established for chronic disease risk because the risks are not considered acute toxicity.
Why Sodium Has a CDRR Value
Based on a comprehensive review of the scientific evidence, the National Academy of Medicine concluded that there was sufficient evidence to establish a CDRR specifically for sodium. The primary reason for this was the strong link between high sodium intake and cardiovascular disease risk.
The Link Between Sodium and Blood Pressure
Numerous studies show a clear and significant relationship between dietary sodium intake and blood pressure. Excessive sodium leads to water retention, increasing the fluid volume in the blood vessels and raising blood pressure. This effect, often termed 'salt sensitivity', can cause hypertension, a major risk factor for heart attack and stroke. While individual responses to sodium vary, population-level evidence is clear: reducing sodium intake lowers blood pressure.
High Sodium and Cardiovascular Disease Risk
Beyond just blood pressure, high sodium intake is directly associated with an increased risk of cardiovascular disease (CVD) events. A meta-analysis published in 2020 found that for every 1 gram increase in dietary sodium per day, the risk of CVD increases by 6%. Given the widespread high intake of sodium in many Western countries, this represents a significant public health issue.
Sodium CDRR Values by Age Group
Sodium CDRR values are designed to be relevant for various life stages. The National Academies of Sciences established the following guidelines:
- Adults (ages 14+): Reduce intake if above 2,300 mg per day.
- Children 9-13 years: Reduce intake if above 1,800 mg per day.
- Children 4-8 years: Reduce intake if above 1,500 mg per day.
- Children 1-3 years: Reduce intake if above 1,200 mg per day.
It is important to note that a CDRR was not established for infants under one year of age, as their sodium requirements are based on Adequate Intake (AI) derived from breast milk consumption.
Practical Ways to Reduce Your Sodium Intake
Since approximately 75% of the sodium in typical diets comes from processed and restaurant foods, simply reducing the use of a salt shaker is not enough for most people. Effective strategies include:
- Reading Nutrition Labels: Check the % Daily Value (%DV) for sodium. A general rule is that 5% DV or less per serving is considered low, while 20% or more is high.
- Choosing Fresh Foods: Opt for fresh or frozen vegetables, fruits, and meats over canned or processed versions.
- Cooking at Home: Preparing meals yourself gives you complete control over the amount of salt added. Use herbs, spices, lemon juice, and vinegar to add flavor.
- Requesting Low Sodium Options: When dining out, ask for your meal to be prepared with less salt. Many restaurants will accommodate this request.
- Comparing Brands: When purchasing packaged foods, compare different brands. Some will offer lower-sodium versions of the same product.
Comparison of DRI Values for Sodium
| DRI Category | Definition | Adult Value (>14 years) | Public Health Relevance |
|---|---|---|---|
| Adequate Intake (AI) | The recommended daily intake level based on observed or experimentally determined estimates of nutrient intake by a group of healthy people. | 1,500 mg/day | Prevents deficiency and ensures nutritional adequacy. |
| Chronic Disease Risk Reduction (CDRR) | The intake level above which reduction is expected to decrease chronic disease risk. | Reduce intake if above 2,300 mg/day | Addresses population-wide health risks from excessive consumption. |
| Tolerable Upper Intake Level (UL) | The highest average daily intake likely to pose no risk of toxicological effects. | Not Determined | Not established for sodium, as chronic disease risk is addressed by the CDRR. |
The Role of Potassium in Moderating Sodium Effects
The interplay between sodium and potassium is crucial for managing blood pressure. While high sodium intake can increase blood pressure, adequate potassium intake can help mitigate this effect. Potassium helps the kidneys excrete excess sodium and promotes blood vessel relaxation. Therefore, public health interventions often focus on both reducing sodium and increasing potassium intake, which can be achieved by consuming more fruits and vegetables. Despite its benefits, potassium does not currently have a CDRR value, as the evidence for an intake-response relationship with chronic disease was not deemed sufficiently strong when the sodium CDRR was established.
Conclusion: The Importance of the CDRR for Public Health
In conclusion, the CDRR is a significant addition to nutritional guidelines, and the nutrient it applies to is sodium. The establishment of a Chronic Disease Risk Reduction value for sodium underscores the strong scientific consensus linking excessive sodium intake to chronic diseases like hypertension and cardiovascular disease. By providing clear, age-specific targets for intake reduction, the CDRR offers a framework for public health initiatives and guides individuals in making dietary choices that reduce their long-term health risks. As research continues to evolve, it is possible that other nutrients may also be assigned a CDRR in the future, further refining our understanding of how diet impacts chronic disease.
Source: National Academies Press: Dietary Reference Intakes for Sodium and Potassium
